Standard time signatures are positioned on staves with the middle staff line, or only staff line for single-line staves, passing through their center. Large time signatures can be positioned in the middle or at the top of bracket groups, or above staves at system-attached item positions.
Dorico Elements automatically positions time signatures after clefs, key signatures, and barlines.
You can move time signatures to different rhythmic positions in Write mode. They are positioned automatically to avoid collisions.
You can also change the position of time signatures in each layout independently; for example, if you want to show time signatures above the staff at system-attached item positions in some layouts but only once per bracket in other layouts.