Navigate to the handbook page for MuseScore 2: Time signatures
Time signatures are available in the main palette sidebar. You can drag and drop the time signatures onto the score (see palette for general information on working with palettes in MuseScore).
If you need a time signature not found in the sidebar palette, go to Create → Time... to create your own. You can edit the upper and lower numbers in the Create Time Signature pane. Once added, just drag and drop the time signature to the score from the window where you manufactured it. Be aware that it will not appear in the pallet.
In most cases, you'll only need to edit the first of the upper numbers. The additional upper numbers are for additive meters , which contain multiple upper numbers separated by a plus sign.
Time signatures you don't need (any longer) could get removed in the above dialog box via right-click -> "Delete Content".
There are occasions when the actual duration of a measure is different from the duration specified by the time signature. Pickup measures are a common example. To change the actual duration of a measure without displaying a different time signature, see the Properties section of measure operations .