For Debt Collectors
Use the Debt Collection Cease and Desist Letter as it mentions the required language in the Fair Debt Collection Practices Act that requires them to stop contacting the debtor, specifically by phone.
For Employers/Co-Workers (sexual or personal harassment)
If this letter is to be used within a company or organization, it should be sent to the individual conducting the harassment as well as any manager to inform them of what is taking place in the workplace.
For Online Harassment
The letter should be sent to the username’s inbox or any available e-mail that is on file with the individual. If available, the social network should be notified in an effort to have the person removed from the website or application.
Other
For more serious harassment cases, this letter should be sent via certified mail (return receipt) so the sender has physical evidence that the recipient received it. Afterward, if the harassment continues, the victim may be able to file a case on the grounds that the individual conducting the inappropriate behavior was previously notified of their actions.