何~か (some, an unspecified number)

The pattern 何+[counter]+か, meaning 'some, a few, several' — expresses a vague but limited quantity. The か marks the indefinite/uncertain quantity. 何人か ('some people / a few people'), 何回か ('a few times'), 何度か ('several times'), 何日か ('a few days'), 何冊か ('a few books'), 何本か ('several long objects'), 何枚か ('some flat objects').