Applications consume or provide data to the next layer and they run on a specific port . That data is then pushed to transport layer which follows the standards of networking(tcp/udp) and convert the data to datagrams and insert the tcp/udp header.
I guess TCP/IP model(stack) is used in the real world(over the internet) which has four layers.
Hey @divs30 OSI model is just a theoretical model its not practically implemented till now the practical models are TCP/IP models and if you will look carefully in wireshark you will find out that how much layers are their and how to identify which layer it is
OSI model is not used in application. The display shows several protocols used by packets and their details. TCP/IP uses several protocols on each of its layer.
The following image provides some of those protocols for each layer.