I'm going to re answer this because the last answer was kind of confusing.
The only way to get Fissure on a Machamp is in Gen I when it can be taught via TM. There are two different versions of Gen I. The original Gen I, (on the Game Boy,) and the Virtual Console of Gen I, (on the 3ds.) It is impossible to get any Pokemon from the original Gen I games past a Gen II cartridge, because Nintendo did not build a way for Gen II cartridges to connect with Gen III cartridges.
But, if you teach a Machamp on the Virtual Console Fissure, you can transfer it with Poke Transporter, and then Bank, and then Home all the way to Sword and Shield. However, any Pokemon transferred from the Virtual Console editions of Gen I or Gen II are given their hidden ability when they enter a game that has abilities in them. In this case, Machamp's hidden ability is Steadfast. There is no way to change a Pokemon's ability if it has a Hidden Ability.
Hope I could help, if you have any questions please ask.