Hi, and thank you for your question. My name is ***** ***** I'll be assisting you today.
It looks you are being prompted with this error for your operating memory (RAM) on your iPad, and not for your storage capacity.
To resolve this issue, please hold down the Sleep/Wake button at the top-right of your iPad until the power off screen comes up, and then slide to power off the device. Next, press the Sleep/Wake button one more time to restart the device - this will free up the memory space on the iPad and allow you to use it normally from now on.
If you need more help, please use the Reply box below to continue our conversation.
Otherwise, kindly take a moment to rate my service by clicking on (and submit) one of the five stars at the top of this page - this is the only way that I'll be credited for assisting you today. Thank you.
PS: Please do NOT accept any remote assistance offer (simply "X" it out) if it shows up on this page at any time; it's sent out automatically by our site, and not by me. We do not need to do a remote session for your issue; I'll reply back to you below now.
Also, to prevent this prompt from showing up anytime in the future as well, please be sure to close out unused apps often, while using your iPad. You can do this by tapping the Home button at the bottom twice quickly, and then swiping up to close out any open app that you don't need to use.
Do let me know if you have any questions or concerns; thank you.
Just a friendly reminder; if the above steps resolved your issue, kindly do not forget to submit a positive rating by clicking on one of the five stars at the top of this page. Otherwise if you are still having issues, do reply back to me using the Reply box below. Thank you.