Microsoft offers a primer on tech support scams.
Tech support scams are an industry-wide issue where scammers use scare tactics to trick you into unnecessary technical support services to supposedly fix device or software problems that don't exist.
At best, the scammers are trying to get you to pay them to "fix" a nonexistent problem with your device or software. At worst, they're trying to steal your personal or financial information; and if you allow them to remote into your computer to perform this "fix," they will often install malware, ransomware, or other unwanted programs that can steal your information or damage your data or device.
Scammers may call you directly on the phone and pretend to be representatives of a tech company. They might even spoof the caller ID so that it displays a legitimate support phone number from a trusted company. They'll probably ask you to install applications that give them remote access to your device. Using remote access, these experienced scammers can misrepresent normal system messages as signs of problems.
Scammers might also initiate contact by displaying fake error messages on websites you visit, displaying support numbers and enticing you to call. They may also put your browser in full screen mode and display pop-up messages that won't go away, apparently locking your browser. These fake error messages aim to scare you into calling their "technical support hotline".
You can read the rest of the piece and watch a video about how to avoid tech support scams via the below link: