Presuming you accidentality saved your login password and you do not want your information from being unintentionally saved or used in your browser.
Please follow these steps to disable and clear it:
Google Chrome Instructions
In Google Chrome, you can turn off autofill data, and delete the data before
I. Turning Off Autofill in Chrome
Step 1. Click the Chrome menu icon. (In the top right of the browser)
Step 2. Click on Settings menu.
Step 3. In the "Autofill" section, expand the area for which you wish to disable Autofill.(In this scenario i choose Password)
Step 4. Turn it off and the settings will save the changes
II. Clearing Autofill Data in Chrome
Step 1. Press CTRL+SHIFT+DEL on your keyboard
Step 2. Go to the "Advanced" tab.
Step 3. At the top, choose “All Time” option to erase the autofill from the very beginning
Step 4. Make sure that the “Autofill Form Data” is checked.
Step 5. Click "Clear Data." to continue the process
In Google Chrome, you can turn off autofill data, and delete the data you have inputted before
I. Turning off Autofill in Firefox
Step 1. Click on the Firefox menu icon. (In the top right of the browser)
Step 2. Click on Settings.
Step 3. Select "Privacy & Security.", and scroll down until Logins and Passwords section.
Step 4. In the "Logins and Passwords" section. uncheck "Autofill logins and passwords." The system will automatically save your settings.
II. Clearing Autofill Data in Firefox
In the "Time Range to Clear" dropdown menu, select “Everything.” to erase the autofill from the very beginning
Make sure “Form & Search History” option is checked.
Click OK to continue.
DISCLAIMER: Delete autofill in Firefox may also delete your browsing history.