Seems you have Windows tablet read below and follow the instructions.
You need to choose the second option to reset from your Windows 8 tablet's logon screen. See how to reset Windows 8 password before performing following steps:
Step 1: Start and go to the login screen, look for the power icon on the lower right hand corner of your tablet's screen. Tap on it.
Step 2: Press and hold the Shift key.
Step 3: As the Shift key is clicked or pressed, simultaneously tap on Restart, the tablet will then restart. Now, you will see a screen where you will be asked to choose an option. Tap on Troubleshoot.
Step 4: Finally, choose Reset option, this will begin the factory reset. When using this method, it is best to have a keyboard connected with your Windows 8 tablet for the easy following of the steps. In case you do not have a keyboard you can connect to, start the On-Screen keyboard, which can be found on the options at the lower left hand corner of your tablet. You can find an icon there that represents the Ease of Access. Tap on it then choose the on-screen keyboard. Thanks hopefully your problem will resolve.