I need to place images along letter path, so it looks like i would write letters with my image.
In theory you could drag a flower to the swatches collection and use the resulted flower pattern as a fill color of your text. I guess it's useless because the flowers would be clipped strictly along the letter outlines, like this (=ABC)
Another option is to outline the text to curves (Type > Create outlines), remove the fill color and apply a custom scatter or pattern brush which is made by dragging a flower to the brushes panel:
This seems very bulky and mechanical, because virtually all fonts are closed curves, there are everywhere 2 lines. Illustrator hasn't without some inserted 3rd party software any automatic method to remove the double lines, it must be done manually letter by letter with path editing tools. Here the C is edited manually:
The work will be massive for long texts, so as well you could draw the letters manually and get the result faster. In addition you could have varying flower sizes because the brush can be scaled by graphic tablet pressure.
There's one trick which produce quite trashed letters which have only centerline and the text can be typed:
1) A text. It's big and rasterized with high resolution, it's no more editable
2A) Live trace is applied, tracing settings are stroke only, no fill, very wide max stroke width and low pixel accuracy
2B) The trace is expanded and a thin stroke is applied to see if there's some editing needed. Nothing is edited.
3) A scatter brush is defined and applied to the traced stroke. The scaling in brush definitions is 20% to adapt my big flower to the size of the traced letters.
I guess this is not better than manually drawn text. The quality will be better if you use very thin font.
If you make web search "centerline font" you will find the preceding idea and several other methods. Some of them use Inkscape (freeware). Centerline texts are frequently needed for engravings and etchings, so the problem has got some attention.