My teacher told me the sentence "I will intend to do it" is wrong I need to say "I intend to do it" but I'm talking about the future do I not need will?
Here are some other things you can say about the future without using 'will'.
I promise to do it. You will do it in the future. In fact, 'will' is not only not needed, it's wrong. You are promising now. You are not going to promise in the future.
I pledge/swear/vow/undertake/guarantee to do it. All of these things are done in the present, but commit you to doing something in the future.
I plan/intend/mean to do it. The intention is in the present. The doing it will be in the future.