How to make new songs to be on top of the playlist?

See the 'Sort your music' section in:

View albums, playlists, and more in Music on iPhone - Apple Support

1. Tap Library, then tap Playlists, Albums, Songs, TV & Movies, or Music Videos.
2. Tap Sort, then choose a sorting method, such as title, artist, recently added, or recently played.

or see the 'Edit a playlist' section in:

Create, delete, and use playlists in iTunes on PC - Apple Support