If you are in scale plan or above then you can enable the offline payment checkout. 
Go to Settings > Configure Chargebee > Offline payment methods > click 'Enable'. On enabling, configure the offline payment methods which you intend to support.

Offline payment methods supported in Chargebee are:

• Bank transfer
• Cash
• Check
• ACH credit transfer
• SEPA credit transfer

Note: Invoices can be generated for offline payments across all plans (by manually recording payment). For existing users, Offline Checkout is available on the Scale Plan and above. For new users, it is available from the Performance plan and above. Refer to this link to learn more about our Chargebee Plans and Pricing