trying to make my intro video clip for my future videos using my phone

Hello guys! I'm trying to make a intro clip for my future videos using my phone, and I found out that it is not easy to edit videos using just mobile phone, I done so nany errors on making this clip, and also the resolution is very good on my phone but after I finished editting this clip, the video resolution turns out very poor, I wonder what's wrong maybe the problem was from the editing app I use. Does anyone here know any good mobile app for editing videos?, please drop any suggestions in the comment below, thank you in advance hehe.