how do I get letters testamentary from the Probate Court to prove I'm competent in handling my deceased finance estate and assets?

The only way to get “Letters of Office” is to go thru the Probate process. If you are not sure whether a Probate case has already been filed in McHenry County, you can check our online search at www.McHenryCircuitClerk.org. If there is no Probate case filed, and there was a Will, the Will would need to be filed in addition to the documents required for filing a new probate case (i.e. Petition for Letters of Testamentary, Affidavit of Heirship, etc.). If there was no Will, then Petition for Letters of Administration and Affidavit of Heirship would need to be filed to open the Probate case. With this type of case, you would also need to get a Surety Bond. We do have more Probate information and links to Probate forms on the Circuit Clerk’s website at https://www.mchenrycountyil.gov/county-government/departments-a-i/circuit-clerk/civil-information/probate. It may be in your best interest to get the advice from a Probate attorney to help with the process.

If you scroll down in goggle or bing with McHenry Co circuit clerks office civil cases in search header. Scroll down page a little bit .