Do you know what happened just before you saw this? You may have a damaged file.
You can try entering Manage | Database | Fields and double clicking the field definitions for these fields. In the dialog that pops up, there's a tab for storage options where you can turn indexing on. If the field shows indexing on, turn it off, exit Manage | Database, then return and turn indexing back on. This trick re-builds a damaged index.
You may have to replace your file with an undamaged back up. If you haven't modified the design of this starter solution, you can make a new starter solution file and then import your data from this file into the new copy using import records.
Those fields are pop-ups. When a field produces <Index Missing>, it usually indicates 1) that you have changed one of the keys (which relate the tables) to be unstored, global or that you have removed the index in Storage Options for one of those keys (on the child side) or 2) it indicates that the value list (if there is one) cannot index to produce the results you require.
In your case, I suspect that the value list is probably broken. Go to your value lists and find the one which says Customers For Invoices (since that is the value list that your BillTo and ShipTo are based upon). Note that it requires two fields be indexed (the Customer ID and the Customer Full Name) since they both are used in the value list. Now go to your Customers table (File > Manage > Databases > Fields) and select the Customers table. Make sure Full Name says Indexed in the Options/Comments column.
i figured it out thanks