The best way to store bitcoin is to either use a hardware wallet, a multi-signature wallet or a cold storage wallet.
Have your wallet create a seed phrase, write it down on paper and store it in a safe place (or several safe places as backups). However, human errors do occur from time to time, resulting in loss of digital assets.
Having a reputable and professional services provider store the digital assets for you is still the best option given that they have the technical, legal, and capital resources to protect your assets.
