A Data Fiduciary is the person or business that decides why personal data is collected and how it will be used.
Simple example
If an online store asks for your name, phone number, address, and payment details to deliver an order, the store is usually the Data Fiduciary.
Why it matters
Responsibility sits with the Data Fiduciary. You cannot simply say, "our software vendor handled it." If your business decided the purpose, your business must be able to explain and prove the data flow.
What to check
What personal data do we collect?
Why do we collect it?
Where does it go after collection?
Which vendors touch it?
Can we prove consent, notice, deletion, and grievance handling?
Thinking the vendor becomes responsible just because the vendor stores or sends the data.
Start with one customer journey. Mark every place where personal data enters, moves, gets stored, gets shared, and gets deleted.
If this is still fuzzy, do this
Run one real data journey through your business. Do not start with legal language. Start with the person, the form, the tool, the vendor, the message, and the deletion point.