Yes squid and octopuses do have suction cups which are used to hold onto prey they catch to eat.
The squid has suction cups that are attached to the squids tentacles and when the squid gets it's prey the squid uses the suction in it's tentacle suction cups to hold onto the prey so that they can kill the prey and eat the prey.
Octopuses also have suction cups on their tentacles just like squid do.
So it's possible for both an octopus and squid to use their suction cups on a human if you're swimming in the ocean with the octopus or squid.
If you're swimming in the ocean and see an octopus or squid then you should get out of the water because they can attack humans.