1. Click Settings on the Navigation bar and select Payments & Taxes from the drop down

2. Click on Add New Payment Type.

3. Fill the details

Name: We suggest you to use a simple name such as Cash, Card, Gift Voucher etc..(This will be visible in the billing screen while finishing the settlement)

Payment Type: Select the type of payment (ex: Cash or Card) which is applicable for the given name 

Status: Select the Enabled or Disabled option

4. Click Add to finish adding

5. Assign this newly created Payment Type to your desired store. Refer the following article to know How to assign a Payment Type to the Store?