Is it possible to fill multiple mtexts (with fields?) with data from the sheet? Each object in drawing has its title, dimension lenght, etc. All the data I already have in the sheet, so it would be nice to somehow automate it rather than copying all the data one by one.
Yes, it is possible. You can do it in a few ways. By scripting in LISP, VBA, C++, .Net. Depending on the version of the CAD platform You have, and Excel some ways are easier, some more complicated. For now, we not have enough data to respond.
You can also search for ready scripts. But now I can't point You to anything as long as I don't know your background.