As a default option, do include the at sign (@) when prompted to provide Telegram or Twitter user. I have only seen one or two that explicitly instruct you to exclude the at sign, but that is unusual.
Read carefully what they ask you for, since not all Airdrops require the same information.
When prompting for your twitter for example, they could demand:
- The name (i.e. John Doe)
- The User Id/User name (i.e. @JohnD1234) -> most required
- The User profile link (i.e.
https://twitter.com/ JohnD1234)
Likewise, on Telegram they could ask you for:
- The name (i.e. John Doe Tel)
- The User Id/Alias (i.e. @JohnD1234Tel) -> most required
- The User profile link (i.e.
https://web.telegram.org/@ JohnD1234Tel)