For more details see the Login as Customer for Magento 2 extension page.
Use the special button to login as any existing customer just in one click. Grant permissions to sub-admin users to login as customer, as well as monitor the login attempts on the special grid.
To login as any existing customer, please, go to Customers → All Customers and select the required one from the grid. Then, click the Select link. In the dropdown, choose the Login as Customer option to proceed to the user's dashboard on the frontend.
Alternatively, you can select the required customer from the grid. Then, hit the Login as Customer button in the account to automatically login to the user's account.
To see all the login as customer attempts, please, go to Reports → Login as Customer Log.
On the grid you can see all login attempts with the detailed information about them.
Store admin can distribute a permission to login as customer to sub-admin users.
Please, go to System → User Roles and select the role you want to grant permission. Switch to the Role Resources tab. Optionally, switch the Resource Access option to Custom.
You can enable or disable the following role resources:
Find out how to install the Login as Customer extension via Composer.