Where on my W-2 can I find the answer to "is any of this interest from funds with less than 50% of their assets invested in California and U.S. obligations?

That information will not be on your W-2.  Please clarify what section you are in and what you are doing so we can help you.

You get that from entering 1099 Div.    What company is it from?  

I'm in CA and have Vanguard funds. I manually enter mine so I don't know if the import picks up all the right amounts for US Govt Obligations. Years ago I had to make a spreadsheet to calculate the amounts each year. The Treasury fund for 80.06% is the only one of mine that now has over 50% in CA. You have to multiply the Dividends by 80.06% to get the amount to exclude.

Vanguard used to include the extra sheets with the 1099 statement but now you have to get them online to see which funds you can exclude and how much. I go though and circle all my funds.