what are the example of invitation to

Firstly, to understand the term "invitation to offer," it is crucial to understand the term "offer" and not misinterpret both as one. 
Section 2 (a), Indian Contract Act, states that a proposal/ offer is made when one party conveys to another party that they would or would not do something for them. In contrast, the Indian Contract Act of 1872 does not define an invitation to offer, and an invitation to offer is an assertion of a person's willingness to enter into contract negotiations and should not be confused with an offer. No specific party intends to enter into a contract in case of an invitation to offer. The seller has the option to enter into a contract with the person who makes the best offer from the general public. The seller makes the offer, which is the essence of an invitation to offer. In contrast to an offer, an invitation to offer does not have legal ramifications.
The example of an invitation to offer case: In Harvey vs. Facey (1893), the defendants were the owners of Bumper Hall Pen, a plot of land. A telegram was sent to Facey, which said, "Will you sell us Bumper Hall Pen? Telegraph lowest cash price-answer paid."
"Lowest price for Bumper Hall Pen £900," Facey replied via telegram.
Harvey responded by communicating, "We agree to buy Bumper Hall Pen for the sum of £900 requested by you. Please dispatch us your title deed in order that we may get an early possession."
Facey then expressed that he did not want to sell.
The price quotation, in this case, was ruled not to be an offer.
According to the House of Lords, the telegram was an invitation to offer, not a valid offer, because the telegram only stated the price and did not explain any other terms or conditions, and could not create any legal obligations.
Other examples for better understanding of an invitation to offer are displaying goods in a store, auctioneering, newspaper advertisements,  an invitation to view an apartment for sale/rent, recruitment offers.

yes, it is an invitation to offer.