Purpose

Lets sibling plugins inject extra fields into the user profile screen — both the in-app profile-completion form and the WP-admin user edit page. Pairs with mam_user_roles_save_addl_user_profile_field_{key} for per-field save logic.

Signature

$fields = apply_filters(
    'mam_add_fields_to_user_profile',
    array $fields,
    int   $user_id     // 0 for new users / signup
);

Returns: array — augmented fields list.

Field shape

array(
    array(
        'key'         => 'my_plugin_loyalty_id',     // usermeta key
        'label'       => 'Loyalty card ID',
        'type'        => 'text',                     // text | textarea | select | yes-no | number | image
        'required'    => false,
        'placeholder' => 'e.g. ABC123',
        'help'        => 'Find this on the back of your card',
        'options'     => array( ... ),               // for select type
        'default'     => '',
    ),
    // ...
)

Example: register a custom profile field

add_filter( 'mam_add_fields_to_user_profile',
    function ( array $fields, int $user_id ): array {

        $fields[] = array(
            'key'      => 'my_plugin_loyalty_id',
            'label'    => 'Loyalty card ID',
            'type'     => 'text',
            'required' => false,
            'help'     => 'Optional — link your existing loyalty card',
        );

        return $fields;
    },
    10, 2
);

// Per-field save logic:
add_filter( 'mam_user_roles_save_addl_user_profile_field_my_plugin_loyalty_id',
    function ( $value, $user_id ) {
        // Validate, normalize, persist.
        $clean = preg_replace( '/[^A-Z0-9]/i', '', (string) $value );
        update_user_meta( $user_id, 'my_plugin_loyalty_id', $clean );
        return $clean;
    },
    10, 2
);

Where the field appears

• Mobile app: profile-completion form, profile-edit screen
• WP admin: user edit page (under the standard profile fields), via Mam_Admin_User_Fields

The same field schema drives both surfaces.

Gotchas

• key is the usermeta key by convention. Prefix with your plugin slug to avoid collisions.
• The two-hook pattern — register the field via this filter AND register a per-field save filter via mam_user_roles_save_addl_user_profile_field_{key}. Without the save filter, the field renders but submissions don’t persist.
• $user_id = 0 during the signup flow — the user doesn’t exist yet. Don’t try to read existing usermeta in that path.
• Required fields block submission until populated. Use sparingly — a required field on the profile-completion form prevents users from proceeding.
• Unsupported type values silently render as text. Verify against the supported list above.

Related articles

• Recipe: Customize onboarding
• Hook: mam_user_roles_save_addl_user_profilefield{key}
• Hook: mam_user_roles_after_create_user
• Hook: mam_user_roles_modify_user_profile_values_before_save

Metadata