Research data and software should be cited for the same reasons as citing to journal articles and other types of publications require citations. The purpose of citing data is to acknowledge the original producer of the data and to help other researchers find the datasets otherwise enable reuse and verification of data, and allow the impact of data to be tracked.
Remember in-text citations and references in the bibliography!
Data availability statement (DAS), also known as data access statement, describes where the data associated with the paper is available, and under what conditions the data can be accessed. DAS is required by many research funders and publishers, and it is a good even when the journal used does not have such a requirement. DAS increases transparency, promotes trust, and is about food scientific practice. It is about the validation, reuse and citation of research data.
DAS includes information about where the data can be accessed, preferably the name of the repository and permanent identifier DOI or URN. Accession number is necessary for some repositories. Also, justification for why access to data is limited should be stated. DASes consist usually only of some sentences.
A simple example of DAS for data with no limitations: " The data that support the findings of this study is publicly available in name_of_the_repository DOI/URN "
DAS does not impose data sharing and opening in repository. It is only a short description about data with a simple and clear statement.
DAS examples e.g. in Cranfield Library DAS examples