There are various strategies for finding a SWOT analysis. Not every resource listed here will provide a SWOT for every company you may be interested in researching. You may have to try more than one avenue before you hit pay dirt.
Often, you will find that much of the kind of information you need may be found in a company's annual report. Most public companies will feature access to their annual reports on their web pages.
Finding a company's annual report on the Internet:
In Google, type: your company followed by investor relations.
McDonald's investor relations
In the annual report, look for Risks