If they accept your offer of peace and open their gates, all the people there will become forced laborers to serve you.

Deuteronomy 20:10
When you approach a city to fight against it, you are to make an offer of peace.

Deuteronomy 20:12
But if they refuse to make peace with you and wage war against you, lay siege to that city.

Joshua 9:8
"We are your servants," they said to Joshua. Then Joshua asked them, "Who are you and where have you come from?"

1 Kings 9:21
their descendants who remained in the land, those whom the Israelites were unable to devote to destruction--Solomon conscripted these people to be forced laborers, as they are to this day.

2 Kings 6:22
"Do not kill them," he replied. "Would you kill those you have captured with your own sword or bow? Set food and water before them, that they may eat and drink and then return to their master."

And it shall be, if it make you answer of peace, and open to you, then it shall be, that all the people that is found therein shall be tributaries to you, and they shall serve you.