A common question in many of the trainings I teach is, should you mark the required fields uniform if most fields in the form are required to install Mark? The short answer is yes. It’s best to have such a specification next to every single required field instead of just having a message such as Oldfield’s are required or all fields are required unless otherwise indicated at the top of the page or no message at all. Most of the time people don’t read small or even large font instructions at a top of a four. When they see a form, they often just jump into filling it. Even when people read such instructions, they might forget the instructions if they happen to be interrupted while they fill out a form, you might think that it will be more efficient to just mark the optional fields, since they are fewer. Unfortunately, to determine that a field is required, people will have to scan the entire form and check for any optional fields. That is not going to happen. Instead, they will use common sense to assume which fields are mandatory and user’s expectations can differ from the designers. The result may be a form of submission error, which will take significant time and interaction cost to address. How should you mark the required fields?
The asterisk has become the standard for indicating mandatory fields, and it has the advantage that it does not take up much space. So yes, it should the asterisk precede or follow the field label. This is unlikely to make a real difference, but one reason to put it just before the field description is to help the eyes easily locate which fields are required by scanning just the leftmost character of the label. If the required fields are specified, should you also specify the optional fields? While it’s not obligatory, marking the optional fields also does logged in the user’s cognitive load. In the absence of that word, the user must look around and infer that a field is optional based on the other fields being marked as required. If the word optional is next to the field squinter, that task becomes a tad easier. Not specifying that a field is optional is not a deal breaker, but doing so is a nice perk.