According to the AISE HS Handbook, plagiarism is a violation of academic integrity. If you try to claim the work of others as your own, you will face consequences:
Students receive zero for the assignment
Before other classwork is graded students are required to redo the assignment in question. Feedback will be provided by the teacher however work will be documented as a 0.
Students will complete a reflection assignment provided by deans and reflect on the assignment with counselors.
Essentially, plagiarism is using other people's words or ideas and pretending that they are your own. According to plagiarism.org, there are many kinds of plagiarism, including "turning in someone else's work as your own," "copying the words or ideas of others without giving credit," and "copying so many ideas or words from another source that it makes up the majority of your work, whether you give credit or not."
Academic honesty is extremely important. If you want to learn more about it, you can watch this video.
Academic honesty doesn't mean that you can't draw upon the views or ideas of others in your writing, but it does mean that you have to correctly cite their work whenever you do. There are loads of resources on the 'Evidence' page of The Writer's Toolbox that can help you with this.
According to the school policy, you have a responsibility to "guard their own work against the cheating efforts of others." This means that if somebody copies your work, you will also receive a zero for that assignment.
In order to prevent this, you can regularly change the password to your school account and resist sharing your work with peers. I understand that this at times, this might be difficult, but ultimately you are helping your peers by not giving them your work. Rather than sharing your work with others, you can ask them guiding questions and verbally offer suggestions that could give them support. Ultimately, we want to support our peers, not replace them.