Assuming your spreadsheet contains you data organize in individual columns with a single row header, and the coordinates of each point (lat, lon) in different columns. You can save your spreadsheet as a CSV file, and use it to plot each row a a point in QGIS. This tutorial explains how, but you can find many step by step guides online: https://www.qgistutorials.com/en/docs/importing_spreadsheets_csv.html

Keep in mind that the approach I suggested works well with thousands of points. If your datasets are really large, 10th's of thousands of points. It might not be possible load all points in QGIS at once. Or you may run into performance issues when trying to perform analysis with all the data.