What is the proper usage of TDA funds?

How can I be authentic with creating security for the beneficiary with the interest generated by the bond (any bond, it doesn’t matter what kind or what value) deposited on account at the treasury gathering estimated 5% interest with at least 1% paid back to the USTD account for use by the trust?  Obviously acquiring properties and other securities is ideal.  What methods are being exacted and used successfully for this purpose?