Are you applying inside the UK or outside the UK?
- If you are applying for the visas online from outside the UK, you can only pay for the IHS surcharge when you are filling out the online application... you are prompted to do it during the application process, so you will likely need to pay it just before you pay for the visa.
If you are applying in the UK for FLR(M):- if you are applying in person, then you have to pay everything together when you book the appointment (£811 visa fee, £500 IHS surcharge and £500 appointment fee).
- if you are applying by post, then you just have to pay the surcharge 'before you complete the application'. Then you mail the application and include the IHS receipt, and then the visa fee is taken from your account when they receive and log the application into the system.
The UKVI website says you can pay for the IHS surcharge by either debit or credit card.
See:
https://www.gov.uk/healthcare-immigration-application/payIn terms of the visa fee, you can pay by one of the following methods:
• Cheque (postal applications only)
• Postal Order (postal applications only)
• Credit card - Visa (including Electron), MasterCard or American Express (Amex)
• Debit card - Delta, Maestro* (including Solo)
• Banker’s draft (payable to the Home Office) (postal applications only)