Only people who have been saved should be baptized, meaning only those who have put their trust in Jesus Christ as their Savior should be baptized. Learn more about salvation

So he commanded the chariot to stand still. And both Philip and the eunuch went down into the water, and he baptized him.

Acts 8:38 (NKJV)

Then those who gladly received his word were baptized; and that day about three thousand souls were added to them.

Acts 2:41 (NKJV)