I see your English is not too good, but from what I gather you want to know who writes the AA lyrics, I just went through the booklets for the CDs I own of theirs and it states 'All songs written and arranged by Amon Amarth', but I would assume that Johan Hegg (their vocalist) writes the lyrics.
No, Johan wrote "Annhilation of.." - at least he's said as much in an interview that was at this site at one point. I think he usually writes most of the lyrics, but the other guys have some input on the stuff, too, in terms of wording and such.