United have scored 45 goals this season, the lowest among the top 10 teams in the standings.
Dane Rasmus Hojlund, 21, who was signed for around for £72 million in August, has netted 13 goals in 34 appearances in all competitions.
Anthony Martial scored twice this season and has been out injured since January. While the club had some help from Argentinian left winger Alejandro Garnacho, who has nine goals in 41 appearances, Marcus Rashford, who had 30 goals last season, has netted eight in 38 games.
Ten Hag had dismissed the possibility of signing a striker in the January transfer window, citing financial fair play rules but has now confirmed the plans in the close season.
"I think it would help," the Dutch manager told reporters on Friday. "You need more options. You need double positioning in every position.
"Some positions we didn't have the choices this season - the striker position, the left-back position - and that has a negative impact on the results.
"We are working in the background on plans with the scouting. The plan is ready but we have to execute."
The manager added that he is open to ideas from the club's new ownership, hoping they would collaborate.
"I trust the new ownership that they will work as quick as possible and bring new good structures and that they can execute (the plans)," he added.
"But we have a way we want to play, so we know our profiles, it has to match the profiles we want."
United are sixth in the league standings on 49 points with seven games remaining.
