How to create an admin account from a local user account

Open Settings menu.

Select Update & security and click on Recovery.

Go to Advanced startup and select Restart now.

After your PC restarts to the Choose an option screen, select Troubleshoot > Advanced options > Startup Settings >Restart.

After your PC restarts, select a startup setting as Safe Mode with command prompt by pressing the corresponding number.

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Open Command Prompt and copy paste the following command and press the Enter key:

net user administrator /active:yes

Close the Command Prompt.

Try to login though Built in Administrator and change the other user account privileges to Administrator.

You may create new user account also and assign the administrative privileges to the account.