The answer to that question depends on what your financial advisor does for you. Many advisors write financial plans for clients. If you want a plan written for you, hire an advisor with the CFP designation (Certified Financial Planner). Some advisors sell life insurance, in which case you might look for a CLU (Chartered Life Underwriter). However, almost all financial advisors recommend or manage investments for you. The highest level designation specifically focused on investment management is the CFA (Charted Financial Analyst). It is widely considered the gold standard of investment designations in the financial industry. So if your financial advisor is handling your investment portfolio, it makes sense that you hire one with the designation demanding the highest expertise on the subject: the CFA Charter.
Here's a brief video about CFA Charterholders.