How Do I Change Default Google Account
Camila Farah

Click on your profile icon if you are signed in you will be taken to the default gmail account.
Make sure that you do this only after all other accounts have been signed out. Log out of all your google accounts. This can be tested by opening up any google page and checking that the account selected. Sign in to the account that you want to make your default account.
I have my personal account i have a google managed work account and my college recently switched to a google managed system. You must log into your default account first. You ll first choose the email address by typing it in and clicking the next button. Up until a few weeks ago whenever i loaded a general google tool like gmail or google calendar it always defaulted to my personal google account the one i use the most.
I have multiple google accounts. You should now see default written next to this account in the account list. Then you ll need to enter in your password for that account. Remember the first account you log in to becomes the default always.
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Now you ll want to select or add your default google account. Select your profile picture on the top right and then click sign out from the menu. If you want to change your default account simply sign out of any one account and then sign back in with the account you want as default alternately keep the one you consider the primary account signed into one browser and use either a private incognito window or a different browser to sign in to other accounts he adds. In order to change the default gmail account simply sign in with the account you want to set as the default.Source : pinterest.com