From the Subscription Section:
Click the grey icon in the top right corner of your map view.
Select 'Subscription' from the dropdown menu.
Under 'Title Credits,' click 'Buy Credit' and follow the instructions.
From a Title:
If you have a title open in the left sidebar, go to the 'Overview' tab.
Click the 'Buy Title Deeds' button.
Click 'Buy Credits' and follow the instructions.
From Projects:
If you're on the Projects page and want to buy credits to bulk-purchase all title deeds from a column, click the three dots in the top right corner of the column.
Select 'Buy All Title Deeds' from the dropdown menu.
Click 'Buy Credit,' choose the amount of credit you want to buy, and follow the instructions.