UPDATE 07/09/20: It also appears that much of the merchandise is available at World of Disney starting today.
The items will be available for purchase online starting July 14th at 10am (Pacific). Items can be shipped (fees apply) or picked up in Downtown Disney at the former ESPN Zone location during a special event July 23rd through July 27th. Guests will need to choose a one hour time slot, with each time slot having have limited capacity.
And now a sample of the merchandise....
A new merchandise collection, of course, starts with a spirit jersey. Guys will also like this new button-up shirt feature icons of the park.
Loungfly has created a coordinating mini backpack for the collection. Top off the look with an ear hat or headband.
Pin traders will want to check out the limited edition pins featuring the Hat Box Ghost, Disneyland map, and classic marquee.
Disneyland Resort Annual Passholders have their own collection of items, including pins, t-shirts, and Wishables plush. Passholders will also get their applicable discounts.
On July 17th at 7am (Pacific), shopDisney will honor Disneyland's actual 65th anniversary by releasing a set of commemorative lithographs.
Quantities are limited on some of this merchandise and purchase limits will apply.
Source: Disney Parks Blog