Despite all this campaigning, there's still no clear winner in sight. One of YouGov's latest polls with The Times showed late Monday that 43 percent wanted to remain, 42 percent wanted to leave and the rest had either yet to decide or wouldn't vote.
One age group that organizations really want to encourage to vote is the younger generation; especially as a new BMG Research poll last week revealed that only 47 percent of 18-24 year olds said they'd definitely vote in the debate, compared to the 80 percent of those aged 65 and above.
"The referendum's decision is going to affect all of us, particularly if you're a young (UK) citizen, as it will affect you for much longer," Kenny Imafidon, partnerships and research coordinator at Bite The Ballot, a party-neutral movement encouraging young people to become active change-makers, told CNBC over the phone.
To encourage more people to register and vote, The Electoral Commission has teamed up with Twitter to launch its #EURefReady campaign, which includes hashtags and neon emojis.
Previous campaigns with Facebook and Twitter have triggered "a really big surge in applications to register", Camps said, highlighting how these platforms are becoming increasingly useful in communicating with younger age groups, especially on politics.
This is a debate that all U.K. citizens "need to be involved and engaged in," as if people don't register or don't vote they can't complain about the outcome, Imafidon said, quoting Channel 4 News anchor, Jon Snow.
"Whatever happens after June 23, we are going to have to live with those consequences, (however U.K. citizens) all need to vote and have their say," Imafidon added, saying "every vote counts."