Login as customer button is the thing every Magento 2 admin panel should have for admin to be able to enter customer account in one click and perform all of the necessary changes or improvements faster.

So, before logging into customer account make sure have Login  As Customer Extension installed on your Magento store, which enables you to login as a customer from several places such as:

Admin Customer Grid

Please, go to Admin Panel > Customers > All Customers.

Magento 2 Admin Panel,Customers

Then find the customer you are interested in and press Login as Customer button.

Magento 2 Login As Customer,Customers

Admin Customer Edit Page

Follow the same directions as previously, but instead of pressing the Login as Customer, choose an Edit button. On a customer edit page find Login As Customer button.

Magento 2 Login as Customer,Edit Page

Admin Order Grid

Please go to Admin Panel > Sales > Orders.

Magento 2 Login as Customer,Admin Order Grid

Afterward, find the order you are interested in and press Login as Customer button.

Magento 2 Login as Customer,Admin Order Grid

Orders View Page

Please, follow the same directions as with the admin order grid. Find a View button and then on order view page press the Login as Customer button.

Magento 2 Login as Customer,Admin Order Edit Page

It is important to remember that to login as a customer from the order's pages, the order should be submitted by a customer, not by a guest.

Invoices Edit Page

Please go to Admin Panel > Sales > Invoices.

 

Find the invoice you are interested in and press View button.

Magento 2 Login as Customer,Invoices

Find the Login AS Customer button.

Magento 2 Login as Customer,Invoices Edit Page

You can login as a customer from the Shipment and Credit Memos pages as well, following the same operations described above.