There are a few different options when looking at installing or upgrading your network switches. A POE switch has power over ethernet connectivity built in, which allows devices such as telephones or access points to receive power as well as ethernet connectivity, reducing the number of wires and power sockets you will need for your equipment to function.
Fixed switches come with a certain amount of ports usually 12, 24, 48 etc and are great for if you are pretty certain you will not go above the number of ports you have available. They can be managed or unmanaged. Managed switches have much more flexibility and can be configured precisely for your business with Vlan and SNMP, whereas unmanaged switches can be used in smaller office spaces or homes where you can just plug in and begin using.
Stackable switches allow you to add additional ports and can grow with you as your business grows. They are usually more expensive than fixed switches and are only normally required for businesses that have large networks to manage.