Thesres a few ways. All below assumes you have the files loaded.
Lyrics:
-If it isn’t visible in the Edit window, got to the little chart-with-a-down-arrow at the right and make sure lyrics is checked.
-You can manually enter (copy/paste) into this field. Similarly, you can use the bigger form under the Lyrics tab at the bottom.
-To auto-lyric, on the main menu (similar on the context menu) Action>Remote Correct>Lyrics.
Artwork:
- You can drag an image straight from a browser right to the individual field.
- Highlight the entire album and drag to the bottom, under the tabs where there’s probably a white square for artwork now.
- Use the artwork tab at the bottom and manually browse for art files.
Both of these can be used in the autocorrector to be done automatically. Artwork is inside “Correct metadata from MusicBrainz” (and should be there by default).