I am newbie in this forum that's why i have facing many problems to find out ANN thread link.
please help me someone.
ANN thread for what?
Signature campaigns get posted under Economy > Marketplace > Services, but you'll need to rank up first before being able to participate in any campaigns:
https://bitcointalk.org/index.php?board=52.0Airdrops and alt coin announcements can be found under Alternate Cryptocurrencies > Announcements:
https://bitcointalk.org/index.php?board=159.0If you're looking for airdrops specifically there's also this very useful website:
https://airdropalert.com/