Premiere pro landscape to portrait 

to Convert Horizontal Video To Vertical Premiere Pro follow these steps
Create vertical videos for social media
1.Drag and drop your video into the Timeline, and Premiere Pro automatically sets the aspect ratio of the project based on the first clip you add.
2.
If you have a horizontal or square video, use the Sequence Settings to adjust it to a vertical format.
3.
Make sure your subject stays in frame with the Auto Reframe feature.
4. If your subject still moves outside of the frame, adjust the reframe as needed.
5. Export your video and adjust the bitrate and resolution.
TikTok, Reels, Shorts, etc ...