What’s new? If you want to add more customized data to any of your documents, you can use Custom fields to do so. Once created custom field can be used as additional parameter for documents filtering.
 
How? Before creating document, you can choose New custom field button in order to create additional field form for entering your information.

After New custom field window appears, you can choose between standard form field types, according to the type of information you want to enter and track later on.

When you decide to use one of suggested forms, you should enter Custom field name and enter values as your information options which you will use in different situations.

This values will be shown as drop down list for choosing between several options you have previously entered.

When you choose between options, the information of chosen option will be listed as additional information on your documents.

Also, this custom field will be shown as one of filtering parameters for your documents. This way you can narrow your search even more.

This was an example of Text box custom field. You can try out different previews when adding some other option from the standard form field types. Once created custom field will always be available to use, with no need of recreating it.