The first step of model creation is defining the input necessary for it. To do this, we should go over all the algorithms of the process that we want to automate and find out which input items are necessary. It is necessary to remember that some algorithms may not need separate inputs. They will use only results obtained in some previous steps, or in other words, the output of other algorithms. Also, some inputs may not be important and can be hardcoded in the model.
The Processing modeler supports the following kinds of input, which can be found in the Inputs tab on the left side of the modeler window: