You can add account details to the “Accounts” tab above the contact’s activity stream on the contact record page.
This tab holds many fields for account details which can be linked to multiple contacts for joint accounts.
To create a new account, you can begin typing in the name of the account in the “Link existing or create new account” field and click the blue “Add new account” button which will bring a new screen up to add details.
You can also link an existing account by typing the name (for example, if you have created an account in another record). When you find the existing account, you can then click the “Link selected accounts” button.