Kenneth I personally always store dates and times in one field in the table.

If the database is for just me, I usually also just have 1 field on forms for editing. However, I have found that many end users struggle with (or complain about having to get the format right) entering a data and a time in one field so sometimes I will have separate unbound fields for entering the date and time and use VBA to assemble them into the original table field.

But keeping the date and time in one field of the table makes it much easier to work with if you are doing any kind of date/time math such as completion dates, or due soon, etc., in my opinion.

Richard does have a lot of videos that work with dates and times. Most of them include the date and time in a single field. Some examples:

Employee Time Clock Shows working with date/time in one field for a time clock
Date Only Shows how to have only the date show unless there is a time value added
DatePart Shows how to pull part of a date/time and expands if you need more info

Donald gave you good advice. I generally recommend storing the completed date and time together in one Date/Time field, such as DateCompleted. Access stores both pieces as a single value anyway, and keeping them together makes sorting, filtering, and doing date/time calculations much easier.

For example, you can easily find all tasks completed today, calculate how long ago a task was completed, or determine whether something was finished before a deadline. If you split them into two table fields, those jobs become more complicated.

On a form, however, you can certainly use separate date and time controls if that is more convenient for data entry. Then combine them and save the result to the one Date/Time field. That is especially helpful if you only want users entering the hour and minute.

The videos Donald linked are good places to start, particularly the Employee Time Clock video. DatePart is also useful once you start wanting to pull out just the date, time, day of the week, month, and so on.