Hey Yulie,
We aren't able to answer you in Spanish, but I hope you'll be able to translate my answer.
You can invite your colleague sharing the board, this will trigger an email, but if you want to share the board without inviting them the only way is to set the board as public and then share the link - However, this will allow anyone with the link sees your information and it can be a security issue, so be careful.
Some article that will help you:
- https://support.atlassian.com/trello/docs/sharing-links-to-cards-boards-comments-and-actions/
- https://support.atlassian.com/trello/docs/adding-people-to-a-board/
- https://support.atlassian.com/trello/docs/changing-permissions-on-a-board/
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