Fencing is a sport that rests on multiple pillars of ability.
Physical: Your strength, endurance, agility and flexibility, all of these are useful in fencing. Any sort of training helps, but you should think about shaping your workout plan to supplement your weaknesses and optimize your strengths.
Technical: Fencing requires very specific movements and sequences to be successful. Learning these and learning how to execute the perfectly is important. Repetition and coaching feedback is key to executing actions correctly.
Tactical: Putting all the pieces together on the strip, so you can execute actions in the right space and time. Watching high level bouts online and seeing how the best in the world solve problems on the strip.
There are lots of resources online, and clubs have been putting more and more online in the wake of covid 19. See the sub-pages for targeted resources.