Hey there, Victoria_Guevara!
Welcome to Apple Support Communities! From your post, it sounds like you've made a screen recording and you're missing the sound.
This might help: Record the screen on your iPhone, iPad, or iPod touch. We're offering this to make sure it was set up correctly, and also to point out that some apps might not let you record the audio.
You'd also want to check the video itself. When you select to play the video, make sure the sound is enabled and not muted: Play videos and slideshows in the Photos app on iPad. This shows you where to look under the Play a video section.
Take care!