Which technique is the most used to prioritize features and what's the best tool to use to do that?

I've managed digital products (apps) from concept to maturity. My experience is with SaaS and apps, so it may or may not be relevant to your situation.

I think the best tool for prioritizing features is to create a features scorecard in a spreadsheet and use that tool to get alignment with your team as to what features get what priority.

Start with defining your business goals (e.g., get more revenue, increase word of mouth, reduce churn, increase retention, etc.). Then assess the resources you have (e.g., number of developers, designers, writers, customer support, sales, whatever your company has to "spend" to create any feature.)

In your spreadsheet, create a row for each potential feature and a column for each goal and each broad category of resource (engineering, marketing, support, for example). Use a small numeric scale (0 - 3) to "score" each feature in each column. For example, a feature may not move you toward goal #1, so you would put "0" in goal #1 column. For the resources, do the same. To the right of all these add a column that subtracts the sum of the resource or "effort" scores from the sum of all the goal column scores. You can multiply these scores by a confidence factor as well.

If you have a team, it's important to get their input on the scoring. This is not something you just show them and ask for approval. You have to involve them in a meaningful way. I can show you how to do that and point you to some examples you can use, if you'd like to give me a call.

At the end of the day, you want to build features with the highest ROI. The best way to determine ROI is to quantify the value of the RETURN (impact) and INVESTMENT (effort) needed. That means scoring.

You should attempt to define all of the variables that enter into the cost/benefit equation which can be assigned a numerical value. Fuzzier items you can still quantify with a scale. You can make this as simple or complex as you want.

I've tested and used many tools to manage this, including:

-ProdPad
-ProductBoard
-Jira
-ProductPlan
-Aha
-Excel spreadsheet

I've found they all vary considerably and none have hit exactly what I needed, such as:

-Complexity for me, developers and business users
-Self-serve stakeholder scoring and weighting (if you want customer or internal feedback)
-Customization for my unique needs

So I built my own which:
Captures ideas, challenges, bugs, any request
Allows users to submit and see their own in a UI
Places an impact score based on what was provided (strategic fit to company goals, subjective user importance, completeness of request, beneficiary is a customer vs internal, etc)
I receive the request and vet it - classify, categorizer, clarify, close it, add it the FAQ with an answer, send it back to the requester for more details or pass it along for developer estimation, etc
I work with engineering to give a point estimate which results in a priority score and estimated dev work hours
I can then build a scored and dated roadmap based on similarity, priority, effort, etc
I can create Kanban cards and push them to a board via Zapier
When things are completed, I close my initial request and the associated feature is added to our feature list

It's not perfect or pretty (not many visuals) but it keeps everything in one place to manage as the fluidity changes daily and I can easily manage and share with anyone in a consistent fashion - since what gets built is ultimately a negotiation where the priority is a subjective value to start from.

I'm a big fan of Pirate Metrics (AARRR), or:

A - Acquisition
A - Activation
R- Retention
R - Referral
R - Revenue

Some people throw another A on there for Awareness. Essentially you will create a spreadsheet with every product feature as a row, and each metric as a column. You then rank each feature against each metric with a 1-5 score.

In addition, I add a separate set of columns for Risk, Effort/Cost, and Impact. Score them the same way.

If you'd like, you can add a weight to each column, based on how important it is to your business at that time. For example, if you're focusing on growth, acquisition may be more important than revenue, so you'd give Acquisition a 5 and revenue a 2. You can then do a blended average, where you multiply each column score by the weight, and sum all the terms together. This will give you an overall score by which to rank all the features.

Hope this helps!