What type of stencils, paint, sealer do I use to paint my front porch

You can use any stencil you want.... I would use a paint made for concrete or specifically for use outdoors.... there is a specialty product called "Patio Paint" for use on outdoor statuary, stones, etc..... I have seen it at Michael's and on Amazon....that should work for stenciling..... be sure and power wash the surface first and let dry... I like Aleene's Repositionable spray glue... apply it and let it dry completely... this is what makes it re-position-able... I found that I needed to reapply it about every 3 rd time I moved it... once again let it dry well....(time for a break any way) You might want to buy more than one stencil.. so the work can progress faster. I used a small rolling pin to make sure the stencil was stuck down as well as possible... I also found that using the "pounce" method to apply the paint worked the best... start in the center of the cut out and work out to the edges...this spreads the paint out better without forcing it under the edges of the stencil. I also use a large piece of foil to "stage" my paint and to remove a good bit of paint from the applicator... I used one of the round foam stencil applicators... then kept it in a plastic bag so it would not dry out.... practice on a piece of scrap wood or cardboard first.... to get the rhythm down before you move on to the real thing. .... Several light coats work better than one heavy one... and let each color dry before you move on to the next one.

You want a clear acrylic sealer, probably with a satin finish. Below is one.

https://www.homedepot.com/p/Seal-Krete-Floor-Tex-1-gal-Clear-Satin-Interior-and-Exterior-Top-Coat-Water-Resistant-Sealer-402001/202599377

I think all you can hope for is "fade resistant" because I doubt anything will survive that AZ sun. Our house faces West and the sun is brutal!

I looked into "sun fading of paint" and found that the Sherwin Williams had the best explanation...they are leading paint suppliers.

https://www.sherwin-williams.com/homeowners/ask-sherwin-williams/problem-solver/dirt-stain-discoloration/fading