Usually “Email capture” is used as “Email Collection” in Korean.
You can compare the 2 websites I referenced.
Hope it helps!

Some biz need to collect e-mail address in order to increase their subscriber and/or customer. They take advantage of this email capture software.

As K.Y.Lee has explained, Email capture is collecting e-mail address in order to increase their subscriber and/or customer. 이메일 추출 or 이메일 수집 might mean just collecting the text of Emails which is not the intention of Email capture. 이메일 계정 수집 or 이메일 어카운트 수집 can be substitute Korean translations. But just for increasing subscriber and/or customer, 계정 or 어카운트 is not necessary.

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Note added at 1 hr (2018-09-28 13:47:54 GMT)
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The asker has meant a tool to capture E-mail. Then phonetic Korean '툴' can be added to 이메일 주소 수집. 이메일 주소 수집 툴.
툴, a tool is now widely used as a computer program or software. I don't think 도구 can make the meaning of an invisible software or program.