Current I have to use two softwares for poster designing.
The text I have to write in corel draw and then I export it in eps and then use Photoshop to give some text effects like bevel shadow etc.
If I write text in Photoshop then that text is very low quality
but in Corel Draw I can't give text effects.
Is there any one software I can use
Corel and PhotoShop should work fine. Depending on the poster you'd likely be using a mix of vector illustration (Adobe Illustrator, InkScape, Corel Draw, etc.) and Raster image editing (PhotoShop, GIMP, etc.) and maybe some page layout software as well (QuarkXpress, InDesign, Scribus).
That said, you normally wouldn't want a raster image editor to be your final file format as you found out, you'll have trouble making crisp type unless you are using a really high end image for it all. For text effects you can only make in PhotoShop, I'd consider doing that in PhotoShop, but then import that back into Corel as an image so you can finish up the rest of the text.
You can use Photoshop for the entire process (it's been a standard for movie posters for almost 20 years) except actual vector drawing (although even there, it's getting more versatile). Dan Sorenson's excellent "Photoshop CS2 for Advertising and Marketing" has examples ranging from comic book art to highway billboards.
The big trick with text in Photoshop is to save as PDF for output to print, which preserves the vector information in the text. A native PSD is read by most applications as a raster image (using the flattened raster image that is saved in the PSD). PDF avoids that problem.
To reinforce what DA01 said: almost any designer works with multiple tools. The Adobe Creative Suite is called a "Suite" because the tools work particularly well together. You can't do top quality work with only one program. Screwdrivers makes poor chisels, and vice versa.
InDesign is the hub of all my print work, because it has excellent vector and raster effects capabilities built in and it's WAY faster than Photoshop for accurate layout. Photoshop is my support tool for fancy raster effects and occasional type effects that InDesign can't yet do, Illustrator for vector art that's beyond InDesign's capabilities.
As an example, here's the Photoshop part of a full-page ad (although it could easily have been a poster). The headline text effect was easily done in Photoshop, and in the rush (I had about an hour to create this) I didn't think to just do it in InDesign. The supplied artist photograph cuts off just to the left of the performer, so the "beams of light" were added in Photoshop along with the extended background.
I did everything else in InDesign:
It would be interesting what specific effect you do need, because a lot of effects can be done in vectors inside Corel Draw, knowing how to use the tools.
Here are some examples of what you mention bevel and shadow.
A-D are done with just some clicks.
A) Effects > Bisel + Shadow
B) Extrude + Shadow (extrude to 0)
C) Extrude + Shadow
D) Plus perspective and some adjusts on the gradients
E) Is to give an example of the versatility in doing all inside Corel. I'm sure I can push the design way further.
I am used to doing a lot of retouching on cases you think you need Photoshop actually inside Corel Draw, like this exercise: Creating an implied floor with light
Because you need to know the tools.
But there is nothing wrong in combining several applications. Actually, you in most cases need to do that.
Edited sometime later.
If I write text in Photoshop then that text is very low quality
To avoid using Ps for things you do not need, stick to the things you actually need it.
There are a few things that are hard to do in vectors alone, like some blurry effects, in this case, nothing is preventing you to do that part alone, with the proper resolution and size, and with a transparent background.
Actually, this is probably the "optimum" way to process big files.
I must add that you have access to a lot of raster effects to be applied directly inside Corel Draw without needing to leave the application and pretty tight integration with PhotoPaint.
Industry Standard is Photoshop and Illustrator. Both are often used interchangeably. All the bitmap artwork is put together in photoshop and all the type and vector elements, and maybe even the arrangement of all the elements, is done in illustrator. But ultimately it is up to you to develop your own workflow.
For many years I used Illustrator for most poster designs, and occasionally InDesign if doing a project where many iterations of a set of related poster designs needed to be done using datamerge - these days my primary design tools are Affinity Designer and Affinity Photo - and I must say agree that I've no conceptual issue with jumping from vector to pixel and back as needed - though in truth with Affinity Designer I do far less of that than I used to with an Illustrator based workflow, because I have easy access to adjustment filters there too.
I used adjustment filters for the colour variations seen in the darker area in these icons area I developed for a client's (and my continuing) use - the base vectors are all the same colour minus the adjustment filters.
So for me it depends greatly on the task being performed whether I need to jump app-to-app - for literally bevel and shadow, I have those in my vector app of choice.
Hope that helps some.
