2022.06.13 As of IOS 14.5, there is still no manual focus adjustment in the phone or tablet's native.Camera.app. Maybe there will never be.
It appears that to focus at a different distance, you can lock the point of focus by pressing and holding the screen with your finger on a certain, chosen point. If you want to focus on far-distance, aim the phone to include a far-distant point, lock that point, then re-compose the frame to include what you want.
When it locks, the Camera app will lock the focus distance, exposure level, and color balance determined by the sensor - for the area around the lock-point. When you set the lock, you can manually bias the exposure + or - up to 8 f-stops from the exposure the camera has determined automatically. Do this using the slide-area to the right of the yellow focus-box that appears around your locked focus point.
The camera app does not include any other mechanism to modify focus when taking photos. The focus / exposure / white-balance locking has been available since at least IOS 12. As mentioned in the comments, it may be possible that a different camera app could set +/or lock focal-distance using software.