In sibelius scoring software, the following steps can be taken to remove the small arc below the lyrics:

1. Open sibelius software.

2. At the top of the software interface, find and click "Settings".

3. In the settings menu, find the "Lyrics Settings" option, and then click Enter.

4. On the lyrics setting page, select the small arc, and then click OK.

After completing the above steps, you can successfully remove the small arc below the lyrics.