Sometimes I am so lazy to make underlines by using Line Tool
And the underline on text function on Photoshop is a bit blurry
When I zoomed :
There is 2 pixels (like 1 pixel semi-transparent extra)
Any trick or setting can I fix this ?
Edit > Free Transform tool. Zoom in (more than 200%) and use the up/down arrow keys to nudge the text by sub-pixel values until the underline go crisp. That's the only workaround I know.
If this is still in text format, check the setting that controls the text clarity on the toolbar. Try different settings from what you are currently using. It may be set to "smooth" and your text is soft in places. See the image below.