Как решить проблему с php.ini?

Пытаюсь запустить composer чтобы тот стянул проект, но выходят вот такие ошибки:

Problem 1 - Installation request for erusev/parsedown 1.7.3 -> satisfiable by erusev/parsedown[1.7.3]. - erusev/parsedown 1.7.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 2 - Installation request for laravel/framework v6.4.0 -> satisfiable by laravel/framework[v6.4.0]. - laravel/framework v6.4.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 3 - Installation request for lcobucci/jwt 3.3.1 -> satisfiable by lcobucci/jwt[3.3.1]. - lcobucci/jwt 3.3.1 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 4 - Installation request for league/commonmark 1.0.0 -> satisfiable by league/commonmark[1.0.0]. - league/commonmark 1.0.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 5 - Installation request for maknz/slack dev-laravel-any -> satisfiable by maknz/slack[dev-laravel-any]. - maknz/slack dev-laravel-any requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 6 - Installation request for sentry/sentry 2.2.2 -> satisfiable by sentry/sentry[2.2.2]. - sentry/sentry 2.2.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 7 - Installation request for xsolla/xsolla-sdk-php v4.0.2 -> satisfiable by xsolla/xsolla-sdk-php[v4.0.2]. - xsolla/xsolla-sdk-php v4.0.2 requires php >=7.1.3 <7.3 -> your PHP version (7.3.12) does not satisfy that requirement. Problem 8 - laravel/framework v6.4.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. - tightenco/ziggy dev-osuweb requires laravel/framework >=5.4@dev -> satisfiable by laravel/framework[v6.4.0]. - Installation request for tightenco/ziggy dev-osuweb -> satisfiable by tightenco/ziggy[dev-osuweb].

To enable extensions, verify that they are enabled in your .ini files: - /etc/php/7.3/cli/php.ini - /etc/php/7.3/cli/conf.d/10-opcache.ini - /etc/php/7.3/cli/conf.d/10-pdo.ini - /etc/php/7.3/cli/conf.d/15-xml.ini - /etc/php/7.3/cli/conf.d/20-calendar.ini - /etc/php/7.3/cli/conf.d/20-ctype.ini - /etc/php/7.3/cli/conf.d/20-curl.ini - /etc/php/7.3/cli/conf.d/20-dom.ini - /etc/php/7.3/cli/conf.d/20-exif.ini - /etc/php/7.3/cli/conf.d/20-fileinfo.ini - /etc/php/7.3/cli/conf.d/20-ftp.ini - /etc/php/7.3/cli/conf.d/20-gettext.ini - /etc/php/7.3/cli/conf.d/20-iconv.ini - /etc/php/7.3/cli/conf.d/20-json.ini - /etc/php/7.3/cli/conf.d/20-phar.ini - /etc/php/7.3/cli/conf.d/20-posix.ini - /etc/php/7.3/cli/conf.d/20-readline.ini - /etc/php/7.3/cli/conf.d/20-shmop.ini - /etc/php/7.3/cli/conf.d/20-simplexml.ini - /etc/php/7.3/cli/conf.d/20-sockets.ini - /etc/php/7.3/cli/conf.d/20-sysvmsg.ini - /etc/php/7.3/cli/conf.d/20-sysvsem.ini - /etc/php/7.3/cli/conf.d/20-sysvshm.ini - /etc/php/7.3/cli/conf.d/20-tokenizer.ini - /etc/php/7.3/cli/conf.d/20-wddx.ini - /etc/php/7.3/cli/conf.d/20-xmlreader.ini - /etc/php/7.3/cli/conf.d/20-xmlwriter.ini - /etc/php/7.3/cli/conf.d/20-xsl.ini You can also run php --ini inside terminal to see which files are used by PHP in CLI mode.