Max clicks, as it sounds will focus on getting clicks. While those clicks will be somewhat relevant to your business they won’t necessary be clicks that are likely to generate conversions (such as filling in a web form or buying something) on your website.
With this strategy you have no control over what you’re bidding on various keywords or the queries that trigger them. Max clicks with a bid limit simply forces Google to never bid over that $5 CPC, for example. And you can only set this per bid strategy, so it applies to all keywords.
Manual CPC is a bid you set at the keyword level as a base. Google may bid anything per auction but over time will try to not exceed your CPC in combination with any bid adjustments you may have set elsewhere, such as for audiences or devices.
This bidding strategy allows you set adjust bids more granularly based on the performance you’re seeing per keyword.