Access ports are connected to only a single VLAN, and do not transmit the 802.1Q tags on any ports recieved or transmitted from the switch. This makes the VLAN tag invisible to any host devices that sit on the other end of the network cable.
By default Cisco catalyst switches place all ports in access mode operating on the default VLAN (VLAN 1). This can be manually set by using the commands switchport mode access to configure the port and switchport access vlan X to set the operating VLAN on that port into the required mode. In recent releases of the Cataylyst operating system ports can be set into access mode via their VLAN name too with the use of switchport access name Y.