Norito, the formal prayers offered during Shinto matsuri, are always written down, and the priest reads them from the paper. This is even true for common norito that the priest has almost certainly memorised. (The purification prayers may be read, but they are not, strictly speaking, norito, so it is also common for them to be recited from memory.) The steps of Shinto liturgy include specific instructions on what to do with the paper, and there are particular rules for folding it, and for how the norito should be written.
At most jinja, there is only one priest, so they write out their own norito. Sometimes, they use a standard norito with a blank for names, and read the names of the people praying on that occasion from a separate piece of paper. At larger jinja, however, the responsibility may be spread around. The September 5th issue of Jinja Shinpō had a short article about the practice at Jingū.
Jingū has a lot of priests, and a number of departments in its administration. One of those departments is the Rituals Department. Within that, the Ceremonies Section is responsible for writing out norito. The senior priest in it is responsible for writing out norito to be offered at the two main sanctuaries, and the second-ranked priest is responsible for norito to be offered at the two most important of the Betsugū, which enshrine the aramitama of the two main kami of Jingū, Amaterasu Ōmikami and Toyoukë Ōmikami. Two lower ranking priests are responsible for the rest of the Betsugū, and the most junior members of the section are responsible for all the other jinja that form part of Jingū.
The author of the article appears to be writing from experience when he talks about the things one has to worry about while writing the norito: Is the line spacing even? Are the characters straight and well-balanced? Are all the characters correct? Is my handwriting good enough to be offered to the kami?
After writing a norito out carefully one character at a time, the priest reads it over multiple times to look for mistakes, and then other people look it over, before it is sent to the building where priests prepare for the matsuri, the saikan. After the norito has been read out and the matsuri has finished, the paper is returned to the Ceremonies Section, and it is then burned.
Each of the most junior priests is responsible for writing out about 530 norito every year. This means that they have to spend a lot of time on it, and it seems that this normally eats into their nominally free time. So, not only is the job stressful, it is also long, and hard work. The author describes it as a particularly tough job, but one that is essential if the matsuri are to be carried out properly.
Personally, I think it would be a good idea to assign one or two more priests to the task.