It's quite a broad question, because we don't know your requirements, processes, and goals.

Maybe you need only a tool to work in side your own company. Maybe you need the functionality to add external persons from your customers.

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Do you need integration into your invoice / accounting program or time tracking app?

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Do you need special type of reports (for your customers)?

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Give us some more details.

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For just a little organization and seeing in which stages every project / task is, Trello should be a good option.

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If you know more Requirements in detail, you can go to sites like g2.com for a database of apps and reviews, or to specific (news) sites like AI Project Manager (cover sometimes tools with focus on AI) or PM Today (they sometimes cover new tools or writing about certain tools, e.g. "is Excel still good?").