Is there anyway to add a person skipped during indexing?
On the US 1930 Census (Alabama, Hale, Harrison, ED 4), there's a family of Clarence Monday, his wife, Nannie Monday, their son, and the grandmother; Susan White. Susan White is not indexed at all, I assume whoever indexed her accidentally skipped her. Is there anyway for me to index her information or will the staff have to fix it?
The index correction function on FamilySearch has no provision for adding (or removing) fields or records, unfortunately.
You can cite the image of the census page on Grandma's profile, but you'll need to jump through extra hoops because of FS's index-centric data structure.
Method 1 (using your Source Box): open the census image in two tabs. On one tab, click Source Box and choose Add To My Source Box. Refer to the image on the other tab to fill out the source title and notes, then click Save.
Go to Grandma's profile, choose the Sources tab/screen, and click Add Source. Choose Attach From Source Box and click Attach next to the citation you just created. (It should be at the top of the list.) Optionally, type a reason (this is one of the places you can mention that she's missing from the index), then click Attach.
Alternately, instead of going to Grandma's sources section, you can stay on the tab where you have the census image open, and click your icon-and-nickname at the top right. Choose Source Box, then click Attach next to the source you just created. (Again, it should be at the top of the list.) Find Grandma's profile using one of the three options (by name, by ID, or from your Recents list), and follow the prompts. (They vary slightly based on the method of finding the profile.)
Method 2 (bypassing your Source Box, but creating an "agnostic" source): open the census image and save its URL. In another tab, go to Grandma's Sources tab/page and click Add Source. Choose Add New Source. Paste the URL into the "Web Page" field, fill out the other fields (referring to the image in the other tab as needed), and click Save.1