Hi @st5564,
Do you want other users to use your own PowerApps license at the same time?
I agree with @cwebb365's thought almost, each user wants to use PowerApps, you must own Office 365 for PowerApps license, or PowerApps licenses (Plan1 & Plan2) or Dynamics 365 license.
If you want the other users (not your own account) to use your own PowerApps license at the same time, I afraid that there is no way to achieve your needs in PowerApps.
If the other users that you mentioned use your own login account, the answer to your question is YES. An Office 365 account could use an app simultaneously within multiple PCs, Mobiles, etc.
Best regards,
Kris