I had filed an amended return 1040X and I received a letter from IRS saying they have adjusted my account. I am not sure how I check my account to see their adjustment?

[VolvoGirl]

That means they got your amended return and adjusted your original return.  That's what you want.

Go by the actual 1040X.  Line 18 should be your original refund amount and line 22 should be your additional refund.  If you paid on your original return it will be on line 16.  If there is an amount owed with the amendment, it will be on line 20.

[Critter-3]

https://www.irs.gov/filing/wheres-my-amended-return