"Reject applications"

Request rejection mode - rejects all incoming requests to your chat or channel

"Accept applications"

Accept requests - the request acceptance mode for your resource can be set for a specific time (in minutes, up to 1440)

It is also possible to make a special effect of Telegram's system notification such as - "The bot wants to send you a message". To do this, you need to set the request acceptance time to more than the time for sending the second message.
More details about this effect here

"Ignore requests"

Ignore applications - a mode for manually accepting requests to your resource. You moderate and accept the users you want yourself

You can also create a special effect for Telegram system notifications, such as - "The bot wants to send you a message". To do this, you need to set the application acceptance time to be longer than the time for sending the second message.
More about this effect here

"Accept the application after clicking'

Link to the topic here