How to find which features have been selected by PCA algorithm? I used PCA function in MATLAB to decrease features on my data set.

By this code I can reduce features from 12 to 8(as an example). It works good but my question is that how can I found with feature have been removed or which feature are selected on the result?

[~, pca_scores, ~, ~, var_explained] = pca(myDataSet, 'NumComponents', 8);
PCA doesn't remove any specific feature.

What PCA does it to calculate linear combinations of your variables in such way that they get "summarized" in fewer variables.

You don't eliminate variables, you reexpress them.