If you want to send a text message and make it from another number than your own usual cellphone number, you have a few options. You can use an online service or a fake number app that assigns you a new permanent or temporary phone number. You can also use a texting service that sends texts from its own number. Note that, if you send messages from a fake SMS number for fraud, harassment or other illegal purposes, you may face legal consequences.
Text Messaging and Phone Numbers
When you send someone a text from your cellphone, the text will show up with your phone number attached. If someone knows your phone number or it's publicly associated with you through, for example, a website or a social networking service, the recipient can know that it's you who sent the text.
In some cases, you may want to send a text message and not have it associated with you. This might be useful for anonymously reporting some sort of information about wrongdoing or to anonymously file a complaint. You may also want to set up a number for your business that's not associated with your personal phone number.
Use a Fake Number App
You can find various apps and websites specifically designed for calling and texting from numbers other than your own.
Some of these are specifically designed for relatively anonymous texting and will assign you a temporary or permanent phone number for calling and texting purposes. Burner and Hushed are two well-known apps for this purpose. Different apps provide different services at different price points, so shop around for one with features and pricing that suit your needs.
You can also use an app that assigns you additional phone numbers that will forward to an app on your phone or directly to your regular phone number. Google Voice and Flyp are two services that can help you set this up.
Some services, like Twilio and Plivo, are designed for businesses wanting to automate texts. Setting them up may take some programming expertise.
Other Options for Texting
You can send a text from a phone belonging to a friend or relative if you want the recipient not to know it's from you, but you run the risk that someone will be able to identify the phone number and trace it back to you or, depending on the content, harass the person who owns the phone number.
Another option is to buy a new phone or set up a SIM card for a new cellphone account to send texts from a number not connected to you — but this can be costly.
Legal and Ethical Considerations
You may also be tempted to use such a text for various kinds of pranks, but make sure to stay on the right side of laws about harassment and fraud and don't do anything that could seriously scare someone or cause someone to get hurt. Use your best judgment and err on the side of caution when sending texts, whether from your usual number or any other return address.
Note that many services that assign you a phone number will keep a record of who is assigned what phone number. If someone sues you or a law enforcement agency investigates you over legally questionable texting, it may be possible to link the number to you through company records.
Additionally, most texting services and phone companies have policies that ban harassment, fraud and other legally and ethically questionable uses. In general, make sure you understand the terms of any texting service you're using.