There are several methods and commands related to tags managing.

Displaying tags

ToggleShow

Checking for tags

HasTag, HasTagInPara, HasTagInString, sysHasParaTags

TestTextParaStyle, TestTextStyle

HasStyle (TxtPosDesc), HasDropNextStyle (ParaStatus)

GetIsParaStyle (Style), GetIsTextStyle (Style)

Getting tags

GetAllTags, GetParaCmds

GetParaStyleType

GetStyle (TxtPosDesc), GetNextStyleName (Style)

GetParaStyle, GetParaStyleName

GetTextStyle, GetTextStyleNamePen

NStyleLibs (Format)

Inserting tags

InsStartEndCmd, StartEndCmd

EditParaStyle, EditParaStyleAll, EditParaStyleChain, EditParaStyleChainDlg, EditParaStyleDlg

SetParaStyle

SetStyle

SetTextStyle

TxtStyle

TxtStyleDlg

Replacing, toggling, deleting tags

ToggleTag

Inserting special signs

InsStartTab

InsTab

InsLastStartTab

DropNextStyle (ParaStatus)

Creating styles

CreateStyle, DeleteStyle, ExpandStyle

Inserting styles

sysInsertByline

ApplyTableStyle, SaveTableStyle