The apps open and then close very soon afterward.

Can you, please, confirm what year and model iPad do you have/own?

The “A” model number can be found on the aluminium back of your iPad, in very small print, right under the larger bold print “iPad” on the back of the iPad.

What iOS/iPadOS version is this iPad, currently, running?

What is the rated, internal data storage space/capacity of your iPad model and how much of this free, internal data storage capacity is left inside of your iPad model?

All of that additional info can be found in the Settings app, General settings panel, About.

Please try to make an attempt to answer all questions asked.

Thank You.

To close/quit background running apps and to manage background running apps in iPadOS.

Tap the link below.

https://support.apple.com/en-us/HT212063

See:

• If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support
• Switch between apps on iPad - Apple Support

Did you tap the 2nd link that Lotus Pilot provided to check ypur iPad’s app switcher and to learn how to quit any, potentially, background running apps?

For much newer design iPad models, without a Home button, try the new simple hard reset procedure for the new 2018/2020/2021 iPad Pros, 2020 iPad Air 4 and 2021 iPad Mini 6 models.

1. Press and release the volume up button.

2. Then immediately press and release the volume down button.

3. Then, press and hold the single sleep/wake/power button You will see the Slide to Power off button, but keep on holding down the power button until you see the Apple logo, then let it go.

Once you have performed all the steps, wait for a few seconds and your 2018 iPad Pro will boot up completely to the iPad Pro’s Lock screen.

Best of Luck to You!