profile-migration.md

users.csv

user_id,email,name,member_number
1,some@emailaddress.com,some user name,123456789

migrate_plus.migration.users.yml

langcode: en
status: true
dependencies: {  }
id: users
migration_tags: null
label: 'Migrate users from csv source.'

source:
  plugin: csv
  track_changes: true
  path: "public://migrations/users.csv"
  delimiter: ','
  enclosure: '"'
  header_row_count: 1
  ids: [user_id]

process:
  type:
    plugin: default_value
    default_value: user
  roles:
    plugin: default_value
    default_value: member
  status:
    plugin: default_value
    default_value: 1
  name: name
  mail: email
  pass:
    -
      plugin: default_value
      default_value: some-value
    -
      plugin: callback
      callable: md5

destination:
  plugin: entity:user
  md5_passwords: true

template: null
migration_dependencies: {  }

migrate_plus.migration.members.yml where membership is the profile bundle type

langcode: en
status: true
dependencies: {  }
id: members
migration_tags: null
label: 'Migrate members from csv source.'

source:
  plugin: csv
  track_changes: true
  path: "public://migrations/users.csv"
  delimiter: ','
  enclosure: '"'
  header_row_count: 1
  ids: [user_id]

process:
  type:
    plugin: default_value
    default_value: membership
  uid:
    plugin: migration_lookup
    migration: users
    source: uid
  field_member_number: member_number
  # or possibly...
  field_member_number/field_member_number_value: member_number
  
destination:
  plugin: entity:profile

template: null
migration_dependencies: {  }