Referencing a portfolio
If you are using the APA referencing style, in the case of a research essay that style requires you to document both in-text citations within your essay sentences, besides providing a separate reference list of your sources at the end.
However, you mention that your given task is to compile a portfolio of journal articles and newspaper articles.
If this is to be a physical compilation using a folder, my recommendation is that you provide just an APA-style reference list of your sources at the end. However, be guided by your tutor. Alternatively, if this portfolio is actually a single, integrated document you could potentially insert in-text citations for each source as well as a final reference list.
Please refer to the official University Referencing Guide for more guidance. If you are using the APA style, you can also consult the APA style website.