Go to Business > Merchants and choose or create a merchant you want to integrate.
Click Merchant settings, then click Leave a request.
Select the purpose for which the API key will be issued, which can be your website or a Telegram bot. Next, provide a link to your project and its name, then Submit. For a Telegram bot, the same information is required. Wait for moderation to finish.
Choose one of the methods presented for domain verification
Using DNS
Using a meta tag on the site
Using an HTML file
Telegram bot (To confirm ownership through the bot)