I want to select a column from my data within a step, but I can't find it as an option

Most of the time, if a column exists in a data set but is not shown as an option, it's because it is not in a format accepted for this choice of columns. Numerical data can be considered as categorical data if the header is more than one row, or if the decimal format selected is not appropriate.

If it is a numerical column, make sure it's recognised as a numerical column. To do so, you can use Explore → Data Types to display the type of each column, and Transform → Specify Data Types in order to modify the type. The different data types in the platform are Categorical (object), Float (float64), Integer (int64) and Boolean (bool).