In the company's AWS account, create resource policies for all resources in the account to grant access to the auditors' AWS account. Assign a unique external ID to the resource policy.

In the company's AWS account, create an IAM role that trusts the auditors' AWS account. Create an IAM policy that has the required permissions. Attach the policy to the role. Assign a unique external ID to the role's trust policy.

In the company's AWS account, create an IAM user. Attach the required IAM policies to the IAM user. Create API access keys for the IAM user. Share the access keys with the auditors.

In the company's AWS account, create an IAM group that has the required permissions. Create an IAM user in the company's account for each auditor. Add the IAM users to the IAM group.