Two questions that might help narrow down the options
1. Will you prefer to send the e-mails via the same platform you collect?
2. Will the signed up people be in the same pool as the future users, or will they exist as a seperate pool? So newsletter-subscribers vs. app-users.
solardev
Is there a reason you don't just use the built in form of your bulk mail provider (eg Mailchimp)? That makes subscriptions, opt-ins, and unsubs/changes a lot easier, since the provider manages all that for you.
Otherwise Google Forms just works and easily saves to a spreadsheet.
satvikpendem
I still use Mailchimp to be honest, I haven't switched. EmailOctopus seems good as well.
1. Will you prefer to send the e-mails via the same platform you collect?
2. Will the signed up people be in the same pool as the future users, or will they exist as a seperate pool? So newsletter-subscribers vs. app-users.