When working with multiple tables, you might need to combine them in different ways by using append or merge. The append process involves stacking tables on top of each other, essentially putting rows from multiple tables under each other in a single table. This is useful when you have similar datasets across different tables and want to consolidate them into one unified dataset. The merge process, on the other hand, involves combining columns from multiple tables based on one (or more) common key or column. This allows you to enrich one table with data from another table by aligning them side by side based on matching values and selected merging logic.