Completely irrelevant answer. Not even related to the OP's question.
Please, don't post, if you don't understand the question!

Not enough info - impossible to answer.
What is your current permalinks structure (what tags are you using) and what is the structure you want to change to?

No. You should have learned to read carefully: the OP very clearly stated
in the question. Permalink structure should always be changed on the Settings > Permalinks subpanel using the structure tags.

Further.
If the original structure was the "default" > then changing it to any other structure will NOT cause any issue: WP will automatically redirect.

However, if the previous structure was something different than the default, i.e. something custom... then WP will NOT redirect and you need to use a plugin, script, .htaccess file etc.

There are certain plugins which may help you.You can try "Custom permalink" or " advance permalink" to configure for your needs.