This is a very broad question and depends a lot on the industry.

Maybe you want to consider implementing Business Process Management (as a management tool) in conjunction with process execution / workflow management systems (software e.g. activiti etc.) to lower administration cost.

Another approach is to migrate to free open source software. This could also help to develop customized software solutions which in turn support your differentiation strategy. Other benefits include openess, cost reduction, no vendor lockin...

Use mass production to reduce cost.

Large company can explore the following IT means to achieve cost reduction (in long term or lower total cost of ownership):

1) IT Process / Robotic Automation e.g. using Orchesrator, Server Automation, Network Automation, Database & Middleware Automation etc (reason: reduce IT labor, reduce human error, consistent & improved SLA, faster speed to provision / de-provision IT resources like virtual machines etc)

2) Cloud Computing (pay per use, elasticity i.e. no over order / provision unused server resources e.g. CPU, Memory, Storage, through self-service portal / reduce call center /  helpdesk, pooled IT resources like server / higher utilization, deploy SaaS so that no need to own the hw, sw & labor to manage the apps or system e.g. Gmail, CRM etc.)

3) Virtual Data Infrastructure / Hosted Desktop Infrastructure (thin client technology / lower acquisition cost, can BYOD, more secure i.e. less tweaking by end users, IT dept has more control on the image, easier patching i.e. update master image & roll-out instead patching many fat clients)

They can also explore the following to achieve differentiation strategy:

1) Big Data Analytics (reason: provide insight to customer needs & trends, the company own business SWOT analysis, better insight about competition, better guided decision-making on new product / services launch or even merger & acquisition etc)

2) Artificial Intelligent Computer System like IBM Watson etc. (explore how these technologies outperform your competition at the same time how to monetize for your company)

Note: above are just some examples off my mind based on experience.  They are many other use cases out there.

Finding your question is related to 1 of my articles i.e. your question is how to use IT / IS as a means to formulate a strategy whereas my article is what strategy (based on Porter 5 forces) a company needs to consider before deciding whether to adopt a particular technology.  If you are interested, you can refer to this link:

https://www.researchgate.net/publication/257303076_Using_Porter_Five_Forces_and_Technology_Acceptance_Model_to_Predict_Cloud_Computing_Adoption_among_IT_Outsourcing_Service_Providers

Article Using Porter Five Forces and Technology Acceptance Model to ...

cloud computing and virtual data infrastructure as Prof Han said is the most implemented information system as the technology it self is economic cost technology as robotic, AI and big data are more expensive to be implemented.

Excellent! All answers seem to complement each other.

Cost reduction due to Information Systems is phenomenal

The generic competitive strategies are focus, differentiation and cost efficiency. I just add the focus strategy.

The organisation following the focus strategy should select whether it offers products and services for the whole market or a selected market segment. It must also develop the strategy and take steps to differentiate itself to achieve some uniqueness or alternatively it must achieve cost efficiency, which involves aggressive measures to develop the processes and structures. Business literature indicates that the organisation failing to develop its strategy, in at least one of the three directions, is in an extremely poor strategic situation and is almost guaranteed have low competiveness and quality (Porter, 1990).

Reengineering and Optimizing your business processes and its implementation through Information Systems may be useful. Organizational transformation aspects considering strategy, technology, process and people should be taken into account for more benefits on the part of an organization. As technology is concerned, the suggestion proposed by Mr. Han Ping Fung, Mr. Thomas Müllerleile may help a lot.

It is indeed a broad question. It has the merit of tying the strategic direction of the company and IT. I think Porter's generic strategies, though important for students to understand strategy, is too simplistic in the real world. A more refined model for strategy is the strategy clock (Johnson, Scholes and Whittington, 2009) which is closer to practice. Not also that no written strategy is needed (for those who do not have one) - a pattern of decisions which gives a certain direction can also be considered as strategy. Once the general direction is know, then IT knows what direction it has to follow. I believe this helps a lot in being selective in IT projects and increases the chances of strategic use of IT.

The company should develop a robust data mining  such would avail the management with ample information for decision making.