How can I explain to others my relationship with XXX person is a QPP (queerplatonic partnership)?

I usually start by telling them that a queerplatonic partnership is a relationship that has a intense emotional bond that doesn't quite fit in the common friendship. What this QPP includes is up to the parties involved and my change from individual to individual or even within each QPP an individual has. I tell them to think of it as soulmates, they don't necesarily need to be lovers, sometimes they might be other times they aren't. If I feel comfortable doing so I might explain on how this relationship is for me and the other parties involved.

It is always up to you how you explain your relationship, and talking with your partner(s) may also be a good idea so you are all comfortable about the way others perceive your relationship. As for the explanation, you can default to terms like "partner", "roommate", "friend" if that makes you more comfortable in some situations. You might also give a short explanation of "We're in love, but not intimately involved" if you feel more accurate information important to you in that situation. You could also take more time to explain in depth about your relationship (perhaps you have a close friend or loved one you want to really understand this) so you could set aside time when you have private time with the person you want to talk with and treat it almost like a coming-out chat where you bring it up, ask what they know or if they have questions, and provide as much information as you (and the other person) feels comfortable with. But above all, it is up to you how you explain your relationship, and you don't have to share or hide anything you and your partner(s) don't want to.

First off, do not explain anything, it is no ones business except for you and your partner. If it comes up due to dating and you want to share the information, rehearse the answer(s) you use. While I think "QPP " is catchy and cool for use within the community, it may not be understood by everyone. In my time we called each other "sisters", "roommates", "significant other"; maybe today "number 1" (ala Capt. Picard) might work better. However you decide, keep it simple, keep it consistent and do not lie.

Assuming that you really need to explain the platonic part (is that really anyone's business?), you could just say that you and X are partners who love each other romantically but not sexually.

First, tell them quite simply, "I'm in a queerplatonic partnership," and then ask them if they know what that means. If they don't, then explain in the simplest terms you can. If they're open to the LGBT+ community then it shouldn't be a huge problem.

You can explain to others about your relationship with XXX is a QPP (Queerplatonic partnership) by explaining how you truly feel. Tell close friend(s) about it, they will help you come out to your family and other not-so-close friends.

I'm actually not sure, but maybe just tell them that it's platonic and explain what that means. It might help them understand.

It is good if you can explain a bit about what it is to others and ask them to research more on QPP to know more about it.

It is very important to establish first that your personal life should be just that, personal. What goes on in your relationships are best understood by yourself and the other individual(s). How you feel about it and how you understand it is truly the most important aspect. However, you should explain the relationship however makes you most comfortable. The amount of information you want to disclose is completely up to you! Share what you feel is important and of value. You could simply say you are in a relationship with someone or further explain by saying you are in an "open-relationship" with XXX or in a "committed relationship" XXX, or simply say just that. "I am in a committed, platonic partnership with XXX". Remember, disclose what is important to you and whatever makes you most comfortable.