If the organization solicits donations in California, it should be current on its filings with the California Registry of Charitable Trusts. Note that most churches and government agencies are not required to file with the Registry.
Use the organization’s Federal employer identification number (FEIN) [nine digits, looks like 12-3456789] — if you don’t have that, be sure to get the name right.
If the organization purports to be a §501(c)(3) charity and isn’t current on its filings, don’t donate.
Here’s a link to the Registry’s search page.