there are multiple allegations of high crimes and misdemeanors, sorta like "probable cause" to justify charges, leading to further investigation...that is the House's responsibility...to investigate...and to determine whether or not the POTUS committed impeachable crimes...
it is possible that the impeachment inquiry does not find sufficient evidence of high crimes and misdemeanors, which would result in no charges being filed...or the House finds chargeable crimes but does not refer them to the Senate...