How to forward messages to Slack in iOS

Create a new app in Slack to handle incoming SMS. Refer to this link to create one.

Enter the app name and the workspace where the app should be created.

Activate incoming webhooks from the webhooks tab. The webhooks tab can be accessed from the app's management dashboard.

Now that webhooks are enabled, create a new webhook by clicking the Add New Webhook to Workspace button.

Slack will ask for the channel the webhook should post to. Select a channel, or create a new channel separately and come back here later.

You'll be sent back to your app settings, where you should see a new entry under the Webhook URLs for Your Workspace section. Your webhook URL will look something like this:

Keep the URL handy, as you'll use it in the app to set up the forwarding rule.

Create a rule.

Add a receiver and select Slack from the options.

In the URL section, enter the URL provided by Slack after creating the webhook.

Send a test message. This lets you verify that the rule is set up correctly and forwards SMS messages according to your criteria.

Save the rule.

Your rule has been set up. Check the Slack app to make sure forwarded texts are received.