how to write on 3d models

Just go to the "insert" toolbar > "Annotations" > "Text" > "Text with leader"
and the click on the part on which you want to write.

Answered with a tutorial: https://grabcad.com/tutorials/how-to-write-on-3d-models

you can also insert a text sketch which will allow you to extrude the text as if it was molded in 3d on your part.

this is the correct sequence:
you must create text on new draw with desired font.... then you must save as .dxf...
now open the dxf and copy-paste on your sketch.... done

you can type3 for catia software

Drafting-->use 'T' text tool--> click on the space--> write ur text--> save it as .dxf format---> then open the file ---> copy the whole text by simply dragging & ctrl+c---> open sketch---> Ctrl+v--> right click on the last sketch from specification tree -->reframe on---> rightclick on the sketch--> specs-->Explode---> fix all together using fix tool--> now you can drag thr=e sketch anywhere on the plane...

thank`s. now i can use it