There are several elements which typically are used to encode handwriting, each of which carries a hand= attribute to indicate whose handwriting it is. These elements include <add>, <addSpan>, and <del>.
The value of the hand= attribute is the key of the person whose handwriting is being encoded. This hand= attribute is an IDREF which must point to the ID of a <hand> element in the TEI header. One <hand> element must appear for each person whose handwriting appears in the text; these <hand> elements are grouped together within the <handList> element inside the <profileDesc>, right after the <langUsage> element.
The WWP does not use any of the other attributes on <hand>, such as ink=, scribe=, or character=.