See >>> Clear Other storage on your iPhone or iPad - Apple Support
“Other” storage mainly encompasses cached information. As for its proportion versus your available space will, in part, be influenced by the model of iPad. Some iPad models have very limited internal storage (perhaps as little as 16GB (from which the iPad will use a high proportion for the Operating System) all the way up to 2TB (which is huge).
With a greater understanding of your iPad model - and storage capacity - we may have a better idea of what is going on. In all cases, the remedy is generally to eliminate cached data - which may be from a number of Apps. The biggest offenders tend to be video streaming Apps, browser Apps (such as Safari) etc. Each App has its own way of removing cached data; this applies to Safari:
Clear the history and cookies from Safari on your iPhone, iPad or iPod touch – Apple Support
Sometimes the only remedy is to backup the iPad to iCloud or iTunes - reset the iPad - and then restore the iPad from the backup.
How to back up your iPhone, iPad and iPod touch – Apple Support
Restore your iPhone, iPad or iPod touch from a backup – Apple Support