There are apps to help you make them. Yes even on phones.
Once you make them though you absolutely must make certain they are under ten megabytes in size. This site will just refuse to accept anything larger than ten megabytes.
Most gif making applications have gif compression options. Yet you still might have to reduce the number of frames per second.
The two apps I use is "Gifshop" as well as "Gif maker editor". Both are on Google play store and are free yet with advertising. Neither leaves a logo on your work fortunately.
The following is what I have made with them...