Why it matters what you type
When you send text to a chat, you pass it to the company that runs the service. What happens to it depends on the service, the plan and the settings: in some places history is stored, in some it can be turned off, in some text may be used to improve models unless you opt out. There is no single rule, so check the privacy settings of the service you use and your employer's policy. Follow a simple principle: do not enter what you would not want to see in someone else's hands, and what you are not allowed to pass to third parties.
Eight kinds of data better kept out
First: passwords, SMS codes, access keys and wallet recovery phrases. Second: bank card and account numbers. Third: scans and numbers of passports and other documents. Fourth: health details of a named person. Fifth: personal data of clients, colleagues and acquaintances: names together with phones, addresses and email. Sixth: trade secrets, non-public financials and company plans. Seventh: closed source code and configuration files that may contain keys. Eighth: anything you are obliged by contract or employer rules to keep confidential.
How to replace personal data with placeholders
Most of the time the AI needs the structure of the text, not the real names. Replace names with “Client A” and “Employee B”, remove phones and addresses, round amounts or replace them with “N dollars”, and company names with “Company X”. The answer will be just as useful, and you put the real data back yourself later. If a document is large, do not paste it whole: describe the situation in your own words or give only the needed fragment without details. Before sending, reread the text through a stranger's eyes: does anything let them tell who this is?
Work data and company policy
Many companies forbid or limit the use of external AI for work materials. Find out the rules from your manager or the security team before pasting a work document into a chat. If there are no rules, it is better to ask than to guess. A good compromise is to use AI for general tasks without work data, for example to improve the wording of a letter after replacing every name and figure. If the company provides corporate access with separate data-handling terms, use that rather than a personal account.
A short checklist before you send
Before you press send, ask three questions. Does the text contain anything that identifies a specific person? Does it contain money, passwords or documents? Am I allowed to pass this to third parties? If any answer is yes, replace the data with placeholders or remove it. Make it a habit to write prompts in anonymised form from the start: you will not forget to delete anything, and the answers will be no worse. And if you did paste too much, check the service settings for deleting history and, if needed, change the password or key.