Import exported ACF Field Groups on plugin activation

acf-json-import.php

<?php
/**
 * Helper function to import the ACF field group if it doesn't exist.
 *
 * @return void
 */
function example_import_acf_field_group() {
	if ( function_exists( 'acf_import_field_group' ) ) {

		// Get all json files from the /acf-field-groups directory in your plugin.
		$files = glob( plugin_dir_path( __FILE__ ) . '/acf-field-groups/*.json' );

		// If no files, bail.
		if ( ! $files ) {
			return;
		}

		// Loop through each file.
		foreach ( $files as $file ) {
			// Grab the JSON file.
			$group = file_get_contents( $file );

			// Decode the JSON.
			$group = json_decode( $group, true );

			// If not empty, import it.
			if ( is_array( $group ) && ! empty( $group ) && ! acf_get_field_group( $group[0]['key'] ) ) {
				acf_import_field_group( $group [0] );
			}
		}
	}
}
register_activation_hook( __FILE__, 'example_import_acf_field_group' );