NI Multisim 14.3 uses (you buy it once, you own it forever). However, each serial number is cryptographically generated for a specific user and validated against NI’s activation servers. Even if you find a number online, the activation server will reject it because it has either been used, blacklisted, or expired.
National Instruments provides different license types depending on your use case: Ni Multisim 14.3 Serial Number
The serial number for is a unique identifier used to activate the software and determine which edition (e.g., Education, Student, or Professional) is enabled . Where to Find Your Serial Number NI Multisim 14