Unfortunately, there is no simple way to create a group mailing list in the Contacts app in iOS. However, you can create a distribution list by typing all the email addresses and copying them into a contact sheet.
1. Open the Notes app on your device and tap the plus sign “+” to open a new note.
2. Enter the email addresses you want to add to the distribution list. Type a less than sign “<” at the beginning of each address and a greater than sign “>” at the end. Separate each address with a comma. For example, < email1 > , < email2 >. Do not include spaces between the “< >” signs and the email address. To make typing easier, you can add the “< >” signs after you enter all the email addresses to save some switching between keyboard layouts.
3. When the list is complete, Select All the addresses and choose Copy.
4. Exit the Notes app by pressing the Home button and open the Contacts app.
5. Tap the plus sign “+” to create a new contact, enter a name for the group, paste the list of addresses into the email field, and tap Done when you are finished.
Alternatively, to make typing a little easier, you could type the list of email addresses on your computer and email it to yourself. When you receive the list of addresses on your iOS device, copy the list from the email and paste it in the email field of the group contact.
If you want to save all the contacts to your computer, go to https://www.icloud.com on the computer. Once signed in with your Apple ID, you can select the Contacts icon to see all your contacts. To export your contacts, select the gear icon in the bottom left of the window, select all your contacts, and choose Export vCard. This will save all your contacts to a file on the computer.