I can’t open my App Store

Wondering why you can't open the App Store.

and

if you are using Phone. Mac or another device.

You may need to be signed in with your Apple ID

Your Apple ID is the account that you use to access all Apple services

and make all of your devices work together seamlessly.

After you log in, you can use the App Store, 

Sign in with your Apple ID - Apple Support

OR

Apple support have an article online that may help:

If you can't open the App Store or iTunes Store, buy content, or edit payment information - Apple Support

If needed:

App Store Support Website

App Store - Official Apple Support

All the best :-)