If you ask this question, I suppose this is either a hobby project or a very small series/prototype. This means that priority is to get something simple and reliable, not to reduce cost by a few cents as in mass production.
So I would recommend the following procedure:
- go to any decent electronics vendor with filtering features (ie not ebay, Amazon or aliexpress, but something like Digikey, RS, Mouser, ...)
- select P-channel MOSFETs
- check filters that you want composents that are in stock, active, and with datasheet (you can also exclude marketplace components if relevant, and set filters on quantities if provided)
- select through hole (or surface mounted if you prefer)
- select VGS_th bellow some low value (between 2 and 3 V): by having a decent margin, you increase the likelihood that the MOSFET is fully on at 5 V
- select a saturation well above your needs. You say 1 A max, so filter for >10 A: this way, you are unlikely to run into thermal issues (often, near maximum, you are limited by duty cycle or need to add a heatsink)
- select the lower end of the Rds_on values (you need <300 mΩ if you want less than 0.3 V drop, so filter for bellow 60 mΩ)
With the above filters, I expect that most remaining MOSFETs will do (on Digikey, I end up with 10 results).
Pick one which size and price suits you, and check the datasheet in details to see if it fits your needs :
- with Vgs = 5 V, at Ids=1 A, Vds is bellow 0.1 V
- Rds_on(@Vgs=5V) * Ids^2 << max power
NB: this procedure is very conservative, so you will end up with some oversized MOSFETs: but excepted if space is at premium, there is no real downside to it (excepted a few cents more, but I suppose it's better to spend 1$ more than to have to read 20 datasheets until you find a suitable MOSFET). If you go for mass production, where 1$ per PCB is far more important than the cost of the time you spend selecting the ideal part, then my procedure is not adapted.
EDIT : procedure if you start from a random P-MOS datasheet :
- check that V_GS_th is smaller than 4.3V (with some margin)
- check that your mosfet supports your max voltages (ie VGS_max>5V and Vds_max>5V) : for such low voltage, you will have a hard time finding mosfets that do not satisfy this constraint. For a 24V application, this becomes non trivial.
- check the Vds vs Ids curve for V_GS =5V, to check that your voltage drop (Vds) is bellow 0.3V @ Ids=1A (for V_GS=5V)
- check that the dissipated power (P=Vds*Ids, taken at VGS=5V from the Vds vs Ids curve (at Ids=1A)) is bellow the maximum you can dissipate (some datasheet tel you this directly, for others you have to use thermal resistance and maximal junction temperature). Be careful about the exact condition of data (sometimes, it is only valid at 10% duty-cycle, or with a huge copper plane on your PCB, ... : read the fine print)
- check the footprint is of a reasonable size/type for your application, and that the price is OK
If I haven't forgotten anything, that's all for your application