Bowman has signed a two-year deal with the Gulls after deciding to leave York City, and Hargreaves has described the transfer as a "really good move for the club" as they look to return to the Football League at the first time of asking.
The 42-year-old told the club's official website: "He is an excellent signing and a really good move for the club. We have a young, hungry striker, who plays on the shoulder of defenders, is good in the air, quick and scores goals.
"He is a big lad as well and possesses a good leap. He had a real purple patch for Hereford a couple of seasons ago and earned his move to York, where it didn't really happen for him as much as it should because he was in and out of the team.
"I've always liked him and he's ready to prove a point. He comes straight into pre-season tomorrow and he's really happy to be down here. There were lots of clubs chasing him, including some of our rivals, so I'm delighted to have him."
Bowman still had 12 months remaining on his contract at York, but after netting just eight times in 42 appearances last season, he was allowed to depart Bootham Crescent.