When first starting a system up without any logo enabled like HP, Dell, or the board manufacturer's own you will see bios version or verion followed by the number like 1014 for example. The support site will have the latest update will be seen along with the drivers for the board like onboard video and sound.
If the latest is a beta look at the next oldest in line to see if that is newer then the version currently on. One small free System Info for Windows(SIW) tool can also help by simply right clicking on the executable you download to create a desktop shortcut. SIW | System Information for Windows by Gabriel Topala | +1-416-733-9743
Some boards have the automatic EZ-Bios feature that will connect directly online to see the latest go on. Otherwise they usually see a Windows installer rather then the old floppy method of copying the update to the root of C as well as having a copy on the 3 1/2" disk along with a dos tool for flashing.
Those required typing the current one followed by typing "ren" and then the exact number of the newer version to see a good flash. The user manual for the board has a section to refer to for the best guide there however. The WinFlash method is quick and easy if that's the option there once the file is downloaded to the drive.
First know the exact make and model of the board to reach the correct support page however. Different models will see different bioses like Award, AMI, or another depending on the chipset at times. A board company will usually see things in different catagories like driver sets, user manual, bios, and other things with an option to list all on one page depending on whether the board is an Asus, Gigabyte, MSI, eVGA, or another manufacturer.