You add an admin to a LINE Official Account (LINE OA) from the account's permission settings, either in the LINE Official Account app or in LINE Official Account Manager on a computer. Only a member with Administrator permission can add one. LINE makes an invite link to pass on; it works once, within 24 hours. The person who gets it logs in with their own account and accepts the role.

How to add an admin to LINE OA

On a phone (LINE Official Account app)

Tap the Home tab, then Settings (the gear icon), then Permissions
Tap + Add and pick the permission type, for example Administrator
Tap Send by LINE, pick the person, then tap Share; the link reaches them in a LINE chat
To send it another way, such as email, tap Generate link, then Copy
The person opens the link, logs in with their own account and selects Accept role

When it is done, their name shows on the permissions screen with Administrator under it.

Source: LINE Official Account Help Center (app), Settings

On a computer (LINE Official Account Manager)

Log in to LINE Official Account Manager with an Administrator account and click the account
Click Settings, then Manage permissions, then Add member
Pick the permission type and click Generate link
Copy the link and send it to the person yourself, for example in a LINE chat or by email; the web page does not send it
The person logs in with their own account and selects Accept role

New to the web version? See LINE Official Account Manager on a computer: a guide

How many admins can a LINE OA have?

LINE's Japanese manual for LINE Official Account Manager says one account can have up to 100 members, whatever their permission, and one person can manage up to 100 accounts. The Thai help center does not state this number.

Source: LINE Official Account Manager manual, permission settings (Japanese)

What each permission can do

LINE OA has 4 permission types:

Administrator: every feature, adds and removes other members, and can sign up for a monthly plan and a Premium ID
Operator: every feature except adding or removing members
Operator without broadcasts: like Operator, but cannot send broadcasts
Operator without insights: like Operator, but cannot see insights

Give Administrator only to people who look after the account; staff who only answer chats need Operator.

Source: LINE for Business guide to LINE Official Account (Thai PDF), admin types

Can't add an admin to LINE OA?

The link is older than 24 hours or someone already used it: generate a new one; one link is for one person
The person making the link is an Operator: an Administrator has to add the member
The account already has 100 members, or the person already manages 100 accounts (LINE's Japanese manual): remove members who no longer need access first
The invited person has no email set on their LINE account: LINE's Japanese manual says they need an email for LINE login first

Added but cannot get in? Check they log in with the same account that accepted the link. More in LINE OA login on computer or phone, and how to fix it

Change a permission or remove an admin

On a computer: Settings, then Manage permissions, click Edit next to the member, pick the new permission type, then Save
In the app: Settings, then Permissions, tap Edit next to the member, pick the permission type, then Save changes
A member with Administrator permission can remove other members from the account
An administrator cannot change or remove their own permission; another administrator has to do it (LINE Taiwan help center)

When a staff member leaves, remove their access the same day.

Several admins answering the same chats

With several admins, customers get two answers, or a chat waits because each person thinks someone else replied. See how to split the work in Split chat work across your team: no double replies

In Easyrobin the whole team answers LINE OA chats from one inbox, and team chat assignment sends each new chat to one person.

FAQ

Can I invite an admin by link?

Yes. Every new member joins through an invite link. In the app you can send it in a LINE chat; on a computer you copy it and send it yourself.

When does the invite link expire?

24 hours after it is made, and it works once. If it expires, generate a new one.

What account does the invited person need?

They log in with a Business ID: either a LINE account with an email and password set, or a business account that uses an email. See the Business ID help center

Can an Operator add an admin?

No. Only a member with Administrator permission can.

Summary

Add an admin to LINE OA from Permissions in the app or Manage permissions on a computer: pick the permission type, generate a link and send it. The link works once within 24 hours. Give Administrator only to people who look after the account, and remove access as soon as someone stops working for the shop.

How to Add an Admin to LINE OA on Phone and Computer