In couple ways:

- Premium - a monthly subscription that gives some additional gimmicks

- Ads - they sell context-based ads in some large channels

- Crypto - they developed and invest in TON which used to be fully theirs (maybe still is? idk) and it's incorporated in the app

- Paid features inside the app, like you can buy their in-app currency to then use it in bots and whatnots

I think these are the main ways, also their CEO is a billionaire which is supposed to cover the rest of expenses and can gather investors to help.

Edit: sorry I suck at formatting

Selling the ads. Also cooperation with Russian government

Ask an investor? Matt Mullenweg is one.

I suppose just like any other open source company etc…. By fund raising or Donations.

[dead]