If you need to refer to your data in e.g. a paper, it is very important that you can point to your data in a precise way. This is often solved by having a persistent identifier (a kind of link) referring to your data set once it is stored in a suitable repository.
Using Digital Object Identifiers (DOI) is a good method for creating persistent identifiers. Most repositories allow you to generate the DOI’s for use. Often you will need to reserve the DOI before you publish any type of data, as you will need the DOI for your publication.
If you are not able to make your data publicly available upon time of publication of your article or similar, you might need to write what is known as a data availability statement. This will often be included in the template of a specific publisher. See SpringerNature for an example of data availability statements.
Questions for making data referenceable and citeable: