Answer:

OPTIN

AnswerCrossword Clue
OPTINGet on board
OPTINChoose to participate
OPTINDecide to take part
OPTINDecide to participate
OPTINAgree to participate
OPTINElect to take part
OPTINChoose to join
OPTINAgree to join
OPTINSay yes
OPTINAgree to take part
OPTINChoose to take part
OPTINElect to join
OPTINSign up for an offering
OPTINSign up to receive email alerts, say
OPTINDecide to join
OPTINSign up for an offering, e.g.
OPTINDecide to join, e.g.
OPTINAgree to accept email ads, e.g.
OPTINAgree to receive marketing email, say
OPTINJoin
OPTINJoin voluntarily
OPTINConsciously join