Purchased realm transfer to Mograine but it gives error!

Last night i purchased realm transfer to Mograine and transaction was on pending status and when i woke up i see transaction complete but when i enter my char it says error char transfer “the selected realm is not accepting char transfer at this time”

That’s correct. Mograine transfers has been blocked off, see this thread:

https://eu.forums.blizzard.com/en/wow/t/transfer-restrictions-and-free-character-transfers-now-available-updated-29-sept/379506

If you have troubles with logging in the character at your current realm, open up a ticket to get it looked at.

i saw that but when i made the purchase it was still available.Also after real transfer can i change faction ?

No, there is no faction change in classic