Trades of US equities have what is termed T+2 settlement time. So, if a stock is sold on Monday, two trading days later, on Wednesday, proceeds will be credited to one’s account. Trades on Friday will settle the following Tuesday. This is the current industry standard (before 2017 it was T+3) and not specific to any broker. However, this doesn’t exactly apply to Alpaca accounts.
All Alpaca accounts are margin accounts and are extended credit to cover the ‘float’ between the time one sells a security and when they can use the funds. For practical purposes the settlement time is T+0. One can trade assuming they have immediate access to funds from sales and, conversely, are immediately debited for any purchases. The only times the settlement date may be relevant is for certain corporate actions (eg receiving dividends or applying a stock split) or determining when cash can be withdrawn from an account.
Settlement time is completely separate from day trade rules. To be a day trade, a buy order needs to fill followed by a sell order in the same day (for a short position it would be a sell then buy). The key is 1) it’s determined by the fill date and not the order submit date and 2) the orders occurred on the same date as of US market time which is Eastern or New York time. A buy made during market hours followed by a sell of the same security in after hours trading counts as a day trade because they were both on the same date. This is independent of when the orders actually settle.
So, the question “If I made a day trade on Jan 12th, 2020 and another on Jan 19th, 2020…would that count as 1 day trade cause the other settled? or two?”. First, those are not realistic dates. Jan 12th, 2020 was a Saturday. But that aside, those would count as two day trades. Each one stands on it’s own.
What might be the confusion is the FINRA “3 day trades in 5 days” rule. This simply states that an account will be considered as “Pattern Day Trader” if one makes more than 3 day trades in a rolling 5 day window (only trading days are counted). Again, that’s independent of settlement dates. Also, note if one make more than one day trade in a single day those count as multiple day trades. If one buys, then sells, then buys, then sells, the same stock in a single day that is considered two day trades and count against the 3 max.